Joakim Eriksson

Muscle Sizes and Moment Arms of Rotator Cuff Muscles Determined by Magnetic Resonance Imaging

Biomechanical models which require information on, e.g., joint torque and muscle force are useful in the estimation of when and how mechanical overload of the musculoskeletal system may lead to disorders. The aim was to study the reliability and validity of magnetic resonance imaging (MRI) to quantify muscle sizes and moment arms by MRI and to test selected anthropometric measures as predictors of muscle sizes and moment arms. A total of 20 healthy Scandinavian women (age 22–58 years) participated in an MRI scanning of their dominant shoulder. With a PC-based program the reliability and the validity of the MRI measurements was estimated to be high, and mean anatomical cross-sectional areas (ACSA) and muscle lengths were measured to be 4.0, 9.8 and 12.1 cm2 and 12.0, 12.6 and 12.8 cm for m. supraspinatus, m. infraspinatus and m. subscapularis, respectively. Volumes were calculated to be 48.8, 125.1 and 153.6 cm3. Moment arms were measured with the upper arm in a neutral position and in a functional position of 34° abduction for m. supraspinatus only, and were 2.4 and 2.6 cm. Physiological cross-sectional area (PCSA) and its fiber force component were estimated from dissected fiber length and pennation angle. MRI volume and PCSA were 1.4–1.7 times higher than dissection data, primarily because of age differences. No external anthropometric measures were found to be predictors of volumes or moment arms.

Adaptation of workplaces and homes for disabled people using computer-aided design

A computer-based tool has been developed to support the planning of adaptations for the physically disabled. The prototype development and evaluation were based on six case-studies, which also provided information on the needs and requirements in real-life planning situations. The tool was found useful in supporting an iterative planning process, where it is important to encourage and activate not only the disabled person, but also other people involved or affected. It was positively evaluated by the participants through its ability to enhance the understanding and encourage active participation. The tool was also found useful in supporting the planners (e.g. an occupational therapists) design and evaluation of aspects such as accessibility, clearance and reach, taking into consideration an individuals size and abilities. The present prototypes effectiveness was not satisfactory as modelling was relatively time-consuming. Besides rationalising the 3-D modelling, future development should also include an improved measurement control, collision detection and a simplified control of view-angles and objects. (Less)

Molecular Rift: Virtual Reality for Drug Designers

Recent advances in interaction design have created new ways to use computers. One example is the ability to create enhanced 3D environments that simulate physical presence in the real world--a virtual reality. This is relevant to drug discovery since molecular models are frequently used to obtain deeper understandings of, say, ligand-protein complexes. We have developed a tool (Molecular Rift), which creates a virtual reality environment steered with hand movements. Oculus Rift, a head-mounted display, is used to create the virtual settings. The program is controlled by gesture-recognition, using the gaming sensor MS Kinect v2, eliminating the need for standard input devices. The Open Babel toolkit was integrated to provide access to powerful cheminformatics functions. Molecular Rift was developed with a focus on usability, including iterative test-group evaluations. We conclude with reflections on virtual realitys future capabilities in chemistry and education. Molecular Rift is open source and can be downloaded from GitHub.

Design and evaluation of a software prototype for participatory planning of environmental adaptations

A software prototype to support the planning process for adapting home and work environments for people with physical disabilities was designed and later evaluated. The prototype exploits low-cost three-dimensional (3-D) graphics products in the home computer market. The essential features of the prototype are: interactive rendering with optional hardware acceleration, interactive walk-throughs, direct manipulation tools for moving objects and measuring distances, and import of 3-D-objects from a library. A usability study was conducted, consisting of two test sessions (three weeks apart) and a final interview. The prototype was then tested and evaluated by representatives of future users: five occupational therapist students, and four persons with physical disability, with no previous experience of the prototype. Emphasis in the usability study was placed on the prototypes efficiency and learnability. We found that it is possible to realise a planning tool for environmental adaptations, both regarding usability and technical efficiency. The usability evaluation confirms our findings from previous case studies, regarding the relevance and positive attitude towards this kind of planning tool. Although the prototype was found to be satisfactorily efficient for the basic tasks, the paper presents several suggestions for improvement of future prototype versions.

Computer-Aided Planning of Production, Working and Residential Environments

This paper discusses a computer-aided planning methodology and its applicability for planning of industrial production and working environments as well as for planning of residential and working environments for the differently abled. The methodology has been developed and evaluated in six case studies in mechanical industries and in six case studies related to adaptations for the differently abled. The results from the case studies indicate that computer-supported modelling and visualisation may serve as a common and efficient language facilitating communication about multifaceted environmental planning issues. The methodology is a cost-effective way of demonstrating layout ideas and testing dynamic activities like manufacturing and transportation. Corporate groups comprising people involved in, or affected by, development work seem to be a fruitful approach for cooperation, one which enhances learning and creativity. Such groups may be a proper forum for the dissemination of information, exchange of opinions, utilisation of both expert and lay experiences, and for public testing of current reality or future plans in such a way that mutual understanding between different professional categories is increased, hence promoting internal commitment. (Less)

A planning tool prototype for environment adaptations

In the area of adapting/constructing homes and workplaces for the physically disabled, a computer-based planning tool has been prototyped and evaluated. The prototypes so far have been based on Macintosh computers and commercially available 3-D modeling and multimedia programs. Six case-studies formed the basis for user-oriented prototyping and evaluation. The present prototype was found useful in supporting the planner (e.g., an occupational therapist) in designing and testing several alternatives at an early stage, and in making modifications throughout the planning process. During planning sessions, the prototype supports understanding and communication among the participants, and provides possibilities to interact with the models and make instant changes. Human models can be adapted to an individuals size and abilities/disabilities, and included in the design to evaluate accessibility, clearance, reach, etc. In order to overcome deficiencies in modeling efficiency and interaction tools, such as viewpoint and object control/assessment, further prototyping should concentrate on developing a 3-D model library and a 3-D manipulation/evaluation program. These two components may have to be unique for this field of application and have the potential to become commercial products. >

Effects of acute stress provocation on cortisol levels, zonulin and inflammatory markers in low- and high-stressed men

The virtual version of the Trier Social Stress Test (V-TSST) is an effective and standardized tool for social stress induction. This study aimed to examine gut permeability and physiological and inflammatory markers of reactivity to acute psychosocial stress. Forty young men were classified as high-stressed (HIGHS) or low-stressed (LOWS) according to the Shirom-Melamed Burnout Questionnaire. Cardiovascular reactivity and gut dysfunction were studied along with cortisol, zonulin and cytokines. Gut permeability was shown to be affected within one hour after the psychosocial stress induction, and shown to be dependent on age. Interleukin-6 increased with time, most pronounced at the end of the one-hour recovery after V-TSST, and was positively correlated to age. HIGHS experienced more abdominal dysfunction compared to LOWS. In conclusion, this study is the first to show fluctuations in gut permeability after psychosocial stress induction. This was partly associated with changes in inflammatory markers.