Value of normative belief in intention to use workplace health promotion apps.

BACKGROUND: Mobile applications (apps) have started to be used for workplace health promotion (WHP). However, the factors that lead to the usage of apps in the workplace from the end-user perspective remain unclear. METHODS: To investigate the research gap, the study evaluates a model for the adoption of WHP apps by combining the theory of planned behavior, the health belief model, and the technology acceptance model. A self-administered questionnaire with validated scales among 354 participants was used to evaluate the proposed model for WHP. RESULTS: Although the study indicated a limited overall model fit, interesting aspects were derived. In particular, the study demonstrated that normative belief (especially), perceived usefulness, and attitudinal belief play important roles in the intention to use WHP apps. CONCLUSION: The study is among the first to validate the theoretical models of mHealth adoption for WHP. Moreover, it shows that not only normative belief but also adjustment to several target groups is a necessary factor to be considered in the development and implementation of an app for WHP.

On the determination of residual stresses in additively manufactured lattice structures.

The determination of residual stresses becomes more complicated with increasing complexity of the structures investigated. Additive manufacturing techniques generally allow the production of 'lattice structures' without any additional manufacturing step. These lattice structures consist of thin struts and are thus susceptible to internal stress-induced distortion and even cracks. In most cases, internal stresses remain locked in the structures as residual stress. The determination of the residual stress in lattice structures through nondestructive neutron diffraction is described in this work. It is shown how two difficulties can be overcome: (a) the correct alignment of the lattice structures within the neutron beam and (b) the correct determination of the residual stress field in a representative part of the structure. The magnitude and the direction of residual stress are discussed. The residual stress in the strut was found to be uniaxial and to follow the orientation of the strut, while the residual stress in the knots was more hydro-static. Additionally, it is shown that strain measurements in at least seven independent directions are necessary for the estimation of the principal stress directions. The measurement directions should be chosen according to the sample geometry and an informed choice on the possible strain field. If the most prominent direction is not measured, the error in the calculated stress magnitude increases considerably.

Animal-based model to investigate the minimum tumor size detectable with an electrical impedance scanning technique.

RATIONALE AND OBJECTIVES: The purpose of this study was to determine the minimum tumor size detectable with electrical impedance scanning (EIS) in laboratory animals. MATERIALS AND METHODS: VX2 tumor cells (1 mm3) were implanted bilaterally into the upper leg musculature of five white New Zealand rabbits. EIS and ultrasound (US) were performed before, during, and immediately after implantation and on every 2nd day thereafter until tumors could be visualized with both modalities. This was followed by an extended follow-up regimen until a tumor size of 1 cm3 was reached. Rabbits were anesthetized subcutaneously. RESULTS: Tumors could not be implanted in one rabbit. Neither EIS nor US were performed in one rabbit due to severe skin alterations at the implantation site. No focal increase in conductance was visible before or immediately after tumor injection. The smallest tumor identified with EIS was determined with US to be approximately 8 mm3. The mean tumor size at initial detection was 52 mm3 (determined with EIS). In two cases, the tumor was first seen with US (EIS detection was delayed with a delay of 1 and 2 days, respectively). In all remaining cases, tumors were detected simultaneously with both EIS and US. All tumors were visible with EIS. CONCLUSION: The animal-based model is feasible. VX2 tumors are detectable with EIS. Tumors characterized by a focal spot at EIS could be detected starting at a tumor size of 7.5 mm3.