Search results for "Rotation"

An unusual case of partial midgut malrotation

2009

Orientation Aids for Mobile Maps

2015

Using mobile maps to represent urban, work, or entertainment environments offers new possibilities to plan and carry out tasks. One potentially critical problem in mobile map usage is the misalignment between the user's frame of reference and the frame of reference of the map. In the experiment reported here, three different ‘orientation aids’ were tested in the context of restricted space, such as a large factory hall. The aim of the study was to find out how user interface design can help the user mentally align misaligned frames of reference for efficient mobile map use. The results of the experiment (N = 12) suggest using a ‘you are here’ marker and landmark highlighting, while canonica…

Spatial Cognition 2020/1: Book of abstracts : August 2-4, 2021, University of Latvia

2021

Spatial Cognition is concerned with the acquisition, development, representation, organization, and use of knowledge about spatial objects in real, virtual or hybrid environments and processed by human or artificial agents. Spatial Cognition includes research from different fields insofar as they are concerned with cognitive agents and space, such as cognitive and developmental psychology, linguistics, computer science, geography, cartography, philosophy, neuroscience, and education. Research issues in the field range from the investigation of human spatial cognition to mobile robot navigation, including topics such as wayfinding, spatial planning, spatial learning, internal and external re…

Constant Power Model in Arm Rotation—A New Approach to Hill’s Equation

2014

The purpose of this study was to further develop the constant power model of a previous study and to provide the final solution of Hill’s force-velocity equation. Forearm and whole arm rotations of three different subjects were performed downwards (elbow and shoulder extension) and upwards (elbow and shoulder flexion) with maximum velocity. These arm rotations were recorded with a special camera system and the theoretically derived model of constant maximum power was fitted to the experimentally measured data. The moment of inertia of the arm sectors was calculated using immersion technique for determining accurate values of friction coefficients of elbow and whole arm rotations. The experi…

Redesign of a Reverse Shoulder Prosthesis: Kinematic and Mechanical Study

2014

In this work a commercial reverse shoulder prosthesis has been redesigned to improve performances in terms of range of movements of the implant and stability to dislocation. A kinematic and mechanic study has been performed using a realistic solid model of the prothesised shoulder: in particular, all the components of the prosthesis have been acquired via a 3D laser scanner and inserted in a virtual humerus-glenoid system by reproducing the common surgical procedure. The final model has been used to measure the maximum angles of abduction and rotation of the arm and the shear forces that cause dislocation. Modifications proposed to the commercial prosthesis are: a different orientation of t…

Biomechanical testing of different posterior fusion devices on lumbar spinal range of motion.

2019

Abstract Background Recent minimal-invasive posterior fusion devices are supposed to provide stability and obtain fusion in combination with interbody cages in the instrumented segment. The aim of the present study is to evaluate the primary stability of two minimal-invasive posterior prototypes compared to an established spinous process plate and standard pedicle screw instrumentation. Methods Seven fresh frozen human cadaver lumbar spines (L2–L5) were tested in a spinal testing device with a moment of 7.5 Nm. Spinal stability was determined as mean range of motion (RoM) in the segment L3/L4 during extension-flexion, lateral bending and axial rotation. The RoM was measured during five cond…

Breaststroke swimmer's knee

1980

The cause of the breaststroke swimmer's knee with medial pain of the knee joint has not been clearly identified. Breaststroke swimmers with knee pain were, therefore, examined arthros copically. None showed any other disorders of their knees than medial synovitis in seven of nine swimmers. Since structural abnormalities could be ruled out, biomechanical analyses utiliz ing cinematographic techniques were used to study patients swimming in a special flume with the speed set at 90% of their best competitive performance. The results indicate that the extension and flexion and also in some cases the hip abduction and adduction movements of the whip kick were performed with high peak angular ve…

Aston Medical Duocentric® Reversed Prosthesis: Proposition of New Glenoid Component Design to Prevent Scapular Neck Notching

2015

Medialization of the center of rotation in reverse shoulder arthroplasty (RSA) results in greater excursion of the proximal humerus especially in adduction leading to a mechanical conflict against the neck of the scapula, thus creating a specific complication: scapular notching, in up to 90 % of RSA. We describe our third generation of RSA in Dijon, the Duocentric prosthesis. This prosthesis provides a new proposition to prevent the notching problem with an inferior overhang integrated to the glenoid baseplate. Such an inferior extension prevents the malpositioning of the hemisphere and resurfaces the “critical zone” preventing notching.Phenomenon while a smaller neck-shaft angle on the hum…

Comparison of Postoperative Coronal Leg Alignment in Customized Individually Made and Conventional Total Knee Arthroplasty

2021

Neutral coronal leg alignment is known to be important for postoperative outcome in total knee arthroplasty (TKA). Customized individually made implants (CIM) instrumented with patient-specific cutting guides are an innovation aiming to increase the precision and reliability of implant positioning and reconstruction of leg alignment. We aimed to compare reconstruction of the hip–knee–ankle angle (HKA) of the novel CIM system iTotal™ CR G2 (ConforMIS Inc.) to a matched cohort of the off-the-shelf (OTS) knee replacement system Vanguard™ CR (Zimmer Biomet). Retrospective analysis of postoperative coronal full-leg weight-bearing radiographs of 562 TKA (283 CIM TKA, 279 OTS TKA) was conducted. V…

Prévenir et réduire les risques de sélection de résistances : de la théorie à la pratique, des pistes pour améliorer la durabilité des PPP

2015

SPEPôle GEAPSICT2communication orale invitée, résumé; La résistance est le résultat inéluctable de la sélection exercée par les PPP sur les populations de bio-agresseurs. On ne peut pas empêcher une résistance d’évoluer, mais on peut retarder substantiellement son évolution en mettant en place des stratégies appropriées avant (prévention) et après (gestion) la détection des premiers individus résistants. Le point-clef à retenir pour cela est que plus le contrôle d’un bio-agresseur est basé sur une chimie peu diversifiée, plus le risque de sélectionner rapidement une résistance est élevé. Un exemple type de ce qu’il ne faut pas faire est de contrôler un bio-agresseur présent sur de grandes s…