Cutting the cylinder into squares: The square form factor

In this article we present a method for constructing two-point functions in the spirit of the hexagon proposal, which leads us to propose a "square form factor". Since cutting the square gives us two squares, we can write a consistency condition that heavily constrains such form factors. In particular, we are able to use this constraint to reconstruct the Gaudin through the forest expansion of the determinant appearing in its definition. We also use this procedure to compute the norm of off-shell Bethe states for some simple cases.Comment: 34 pages, 10 figure

During gait with crutches

The goal of this study was to develop a three-dimensional kinematic and kinetic model of the right upper extremity and a Lofstrand crutch in order to analyze joint displacements and loads during crutch-assisted gait. A Lofstrand crutch was instrumented with a six-component load cell to measure forces and moments at the crutch tip. The crutch and the right upper extremity of a subject were instrumented with markers to obtain kinematic data. A biomechanical model based on rigid bodies was implemented in biomechanical analysis software. To demonstrate the functionality of the model, a pilot test was conducted on one healthy individual during Lofstrand crutch-assisted gait. The shoulder extended during the support phase and flexed in the swing phase, the elbow flexed during the swing, and the wrist remained in extension throughout the cycle. In the shoulder and elbow joints, the predominant reaction forces were upward, whereas the internal force moments were flexion and extension, respectively. This tool will be useful when it comes to identifying risk factors for joint pathology associated with pattern gait, aid design or crutch overuse.Peer Reviewe

Fat Oxidation during Exercise in People with Spinal Cord Injury, and Protocols Used: A Systematic Review

Background: The aim of this study was to summarize evidence on energy metabolism through peak fat oxidation (PFO) and maximum fat oxidation (Fatmax), as well as to analyze the protocols used in people with spinal cord injury (SCI) and to examine the main factors related to fat oxidation ability (i.e., age, sex, level of physical activity, and level and degree of injury). Methods: Studies to determine PFO and Fatmax using indirect calorimetry with an arm exercise protocol for SCI patients were included after a systematic search. Other endpoints included study design, sample size, control group, demographic data, level of injury, physical condition, protocol, outcomes measured, and statistical findings. Results: Eight studies (n = 560) were included. The mean value of VO2peak was 1.86 L∙min−1 (range 0.75–2.60 L∙min−1) (lowest value in the tetraplegic subjects). The PFO ranged between 0.06 and 0.30 g∙min−1 (lowest rates: the non-trained subjects with cervical SCI; highest: the tetraplegic subjects). Two types of exercise protocol were found: arm cycle ergometer, and wheelchair propulsion with a computerized ergometer. Five studies used an incremental protocol (2–3 min/stage, different load increments); the rest performed tests of 20 min/stage at three intensities. Conclusion: There are few existing studies measuring fat oxidation in SCI, many of which used small and heterogeneous samples. PFO was lower in SCI subjects when compared with non-injured people performing lower-limb exercise; however, comparing upper-limb exercise, people with SCI showed higher values.This study was funded by the Junta de Comunidades de Castilla La Mancha [PPII-2014-007-A] and the Biomedical Research Networking Center on Frailty and Healthy Aging (CIBERFES), along with FEDER funds from the European Union [CB16/10/00477]. I.R.-G. received a postdoctoral contract from the Universidad de Castilla-La Mancha “Contratos de investigadores postdoctorales para la excelencia científica en el desarrollo del Plan Propio de I + D + I, cofinanciada por el Fondo Social Europeo” (2021/5937). J.L.-M. received a doctoral contract from the Universidad de Castilla-La Mancha “Contratos predoctorales para personal investigador en formación en el marco del Plan Propio de I + D + i, cofinanciada por el Fondo Social Europeo” (2019-PREDUCLM-11385); Plan Propio Universidad de Castilla-La Mancha

Inverse kinematics for upper limb compound movement estimation in exoskeleton-assisted rehabilitation

Robot-Assisted Rehabilitation (RAR) is relevant for treating patients affected by nervous system injuries (e.g., stroke and spinal cord injury) -- The accurate estimation of the joint angles of the patient limbs in RAR is critical to assess the patient improvement -- The economical prevalent method to estimate the patient posture in Exoskeleton-based RAR is to approximate the limb joint angles with the ones of the Exoskeleton -- This approximation is rough since their kinematic structures differ -- Motion capture systems (MOCAPs) can improve the estimations, at the expenses of a considerable overload of the therapy setup -- Alternatively, the Extended Inverse Kinematics Posture Estimation (EIKPE) computational method models the limb and Exoskeleton as differing parallel kinematic chains -- EIKPE has been tested with single DOFmovements of the wrist and elbow joints -- This paper presents the assessment of EIKPEwith elbow-shoulder compoundmovements (i.e., object prehension) -- Ground-truth for estimation assessment is obtained from an optical MOCAP (not intended for the treatment stage) -- The assessment shows EIKPE rendering a good numerical approximation of the actual posture during the compoundmovement execution, especially for the shoulder joint angles -- This work opens the horizon for clinical studies with patient groups, Exoskeleton models, and movements types -

Instrumentation and biomechanical model for kinematic and kinetic analysis of upper limbs during gait with crutches

[EN] The goal of this study was to develop a three-dimensional kinematic and kinetic model of the right upper extremity and a Lofstrand crutch in order to analyze joint displacements and loads during crutch-assisted gait. A Lofstrand crutch was instrumented with a six-component load cell to measure forces and moments at the crutch tip. The crutch and the right upper extremity of a subject were instrumented with markers to obtain kinematic data. A biomechanical model based on rigid bodies was implemented in biomechanical analysis software. To demonstrate the functionality of the model, a pilot test was conducted on one healthy individual during Lofstrand crutch-assisted gait. The shoulder extended during the support phase and flexed in the swing phase, the elbow flexed during the swing, and the wrist remained in extension throughout the cycle. In the shoulder and elbow joints, the predominant reaction forces were upward, whereas the internal force moments were flexion and extension, respectively. This tool will be useful when it comes to identifying risk factors for joint pathology associated with pattern gait, aid design or crutch overuse.This work was supported by a grant from the Castile-La Mancha Social & Health Foundation (Fundación Sociosanitaria de Castilla la Mancha) (PI2010/50). The research for this manuscript was partially funded by a CONSOLIDER INGENIO grant from the Spanish Ministry of Science and Innovation under its HYPER project (Hybrid NeuroProsthetic and NeuroRobotic Devices for Functional Compensation and Rehabilitation of Motor Disorders, CSD2009- 00067). We should like to thank Ana de los Reyes, Antonio del Ama, Beatriz Crespo, Fernando Trincado, Iris Dimbwadyo, Vicente Lozano, and Soraya Pérez for their contributions to this study.Pérez-Rizo, E.; Solís-Mozos, M.; Belda Lois, JM.; Page Del Pozo, AF.; Taylor, J.; Pons, JL.; Gil-Agudo, Á. (2013). Instrumentation and biomechanical model for kinematic and kinetic analysis of upper limbs during gait with crutches. Journal of Accessibility and Design for All. 3(2):135-156. https://doi.org/10.17411/jacces.v3i2.16S1351563

Point-Mass Biomechanical Model of the Upper Extremity During Lofstrand Crutch-Assisted Gait

We propose a point-mass biomechanical model to estimate the forces and moments supported by the upper extremity during Lofstrand crutch-assisted gait. This model is based on the Newtonian classical mechanics and the angular momentum theorem. The system arm-crutch is divided into three segments: 1) crutch, 2) wrist-elbow, and 3) elbow-shoulder. The theoretical model was experimentally validated with a disabled person with spinal cord injury. Two crutch-assisted gait patterns have been chosen to carry out the experimental validation: two-point reciprocal gait and swing-through gait. Six position markers (three placed on the arm and three placed on the crutch) and two force sensors (placed on the crutch) were used in experiments for testing the model. The results were compared with a distributed-mass model based on studies previously published, concluding that the relative mean difference between models is less than 3% Body Weight and 1% Body Weight times Height when forces and moments are estimated, respectively. Some advantages of using a point-mass model are summarized: simple formulation, easy to understand; require less numerical calculation reducing the computational cost; requires less position markers placed on the subject, increasing therefore the comfort of the subject

Online Assessment of Human-Robot Interaction for Hybrid Control of Walking

Restoration of walking ability of Spinal Cord Injury subjects can be achieved by different approaches, as the use of robotic exoskeletons or electrical stimulation of the user’s muscles. The combined (hybrid) approach has the potential to provide a solution to the drawback of each approach. Specific challenges must be addressed with specific sensory systems and control strategies. In this paper we present a system and a procedure to estimate muscle fatigue from online physical interaction assessment to provide hybrid control of walking, regarding the performances of the muscles under stimulation

O106 / #796 FEASIBILITY OF TRANSCUTANEOUS SPINAL CORD STIMULATION COMBINED WITH ROBOTIC-ASSISTED GAIT TRAINING (LOKOMAT) FOR GAIT REHABILITATION FOLLOWING INCOMPLETE SPINAL CORD INJURY. A CASE SERIES STUDY

Transcutaneous electrical spinal cord stimulation (tSCS) is a non-invasive technique for neuromodulation with therapeutic potential for motor rehabilitation following spinal cord injury (SCI). The aim of the present study was to analyze the feasibility of a program of 20 sessions of 30-Hz tSCS combined with robotic-assisted gait training in incomplete SCI. The results of the present work partially belong to a randomized clinical trial that is in progress

Escena de thíasos marino en el Prepirineo aragonés: el hallazgo del opus tessellatum blanquinegro del Forau de la Tuta (Artieda, Zaragoza)

Presentamos los resultados del estudio técnico, iconográfico e iconológico del mosaico bícromo hallado en el yacimiento romano recientemente descubierto de El Forau de la Tuta (en Artieda, Zaragoza, enclave localizado en el Prepirineo aragonés, concretamente en la conocida como Canal de Berdún), y encuadrado cronológicamente entre finales del s. I y principios del s. II d. C. Este pavimento cuenta con una serie de particularidades que le confieren un carácter especial: su extraordinario estado de conservación, su diseño basado en una bicromía invertida con figuras diseñadas con teselas blancas sobre un fondo realizado con teselas negras y la propia iconografía, con dos amores afrontados sobre hipocampos, delfines y veneras. Estas figuras y elementos son propios de un thíasos marino, una iconografía muy popular en ambientes termales o lugares vinculados con el agua. La estancia que decoró ha sido interpretada por varias razones, tales como las propias características del mosaico además de la presencia de un bocel hidráulico y de otras soluciones aislantes de la humedad, como el uestibulum de un edificio termal de grandes dimensiones del que solo conocemos una mínima parte, ya que está siendo actualmente objeto de excavación. Para su registro y documentación se han utilizado diversas técnicas geomáticas de fotogrametría aérea, terrestre y de láser escáner 3D, metodología que ha permitido continuar con el estudio de las estructuras exhumadas a pesar de que, por motivos de conservación, se hayan tenido que volver a cubrir. El yacimiento, además, cuenta con una segunda ocupación altomedieval, conocida gracias a los materiales exhumados y también por la presencia de un silo en el mosaico que aquí analizamos

BRAIN & SPINAL CORD DAMAGE & REHABILITATION

Stroke and traumatic injury in brain or spinal cord are often life-threating conditions and major causes of death or permanent disability with high impact in the health care system. There are several stages of intervention to improve the neurological outcome. Acutely, fast interventions aiming to reestablish cerebral blood flow in ischemic stroke, to stop bleeding after brain hemorrhage, and to reduce edema after contusions are amongst mandatory actions. Current studies aim to develop accompanying strategies for brain cell protection based on enhancing endogenous protective mechanism, blocking cell death pathways, or through immunomodulation. After the acute phase, interventions are intended to promote recovery of function using rehabilitation with state-of-the-art technologies enabled by robotics. Other advanced strategies include cell, gene, and immune therapies, and brain function modulation with the aid of smart nanotechnologies. There is great expectation in the fast evolving novel approaches for improvement of neurological deficits in these unpredictable and devastating conditionPeer reviewe