12 research outputs found
Neck disorder influenced by occupational reward type: Results from effort-reward imbalance model based on IPWS
Effort-Reward Imbalance model is known as one of the survey method of occupational stress and also as an effective element on health condition according to its parameters. Due to types of rewards generally, and reward subscales in this model specifically, each one can have a distinctive effect on health perception, current study is aimed at determination of the most effective reward subscale for managing work-related neck disorder in industries. All of workers who participated in IPWS study (N = 1126), were entered in the statistical analysis stage. After completing personal and organizational information, they responded to Van Vegchel et al. Effort-Reward Imbalance and also Dutch questionnaires for their musculoskeletal disorders. Chi-square and t-test comparisons were performed and the final regression model was presented with a significance level of 0.05. The mean (Standard deviation) age of workers and musculoskeletal disorders prevalence in neck were 33.21 (7.63) years and 34 percent respectively. Also in workers with neck pain, odds ratio between effort and monetary reward, between effort and respect reward, and between effort and security reward in their jobs were 1.35, 2.07 and 1.32 respectively. After elimination of confounders in final regression model, significant correlation was remained only between effort and job respect reward. According to high prevalence of musculoskeletal disorders in neck and also large amount of effort-reward imbalance in Iranian workers, implementing interventions are recommended. Based on results of present study, it is suggested that main intervention must be focused on respect and esteem reward in jobs. © Springer Nature Switzerland AG 2019
Effects of Inhalation Flow Rate on Particle Deposition and Flow Structure in a Model of Tracheobronchial Airway.
Due to the prevalence of respiratory diseases, effective drug delivery to the lungs is important for researchers. The main objective of current study is investigating the transfer and deposition of micron-sized particles (1-10 ?m) as well as airflow structure at different respiratory flow rates (i.e. 30, 60, and 90 L/min) in a realistic airway model according to the CT images of a 48-year-old healthy female. Computational fluid dynamics (CFD) is used for simulation of particle transport and deposition in an airway model that includes mouth-Throat zone, trachea region, and bronchial airways up to the fourth generation and the results were compared with available data in the literature. To investigate airflow structure, velocity contours with streamlines at different regions are obtained. Deposition fraction (DF) is used to present the results of particle deposition pattern. The results show that mouth-Throat region and trachea filters out largest inhaled aerosols, which lead to highest particle deposition fractions for these regions. In addition, increasing the inhalation flow rate, increases turbulence level and particles inertia which result in higher deposition fractions
Effect of laryngeal jet on dry powder inhaler aerosol deposition: A numerical simulation.
Although pulmonary drug delivery has been deeply investigated, the effect of the laryngeal jet on particle deposition during drug delivery with dry powder inhalers (DPI) has not been evaluated profoundly. In this study, the flow structure and particle deposition pattern of a DPI in two airway models, one with mouth-throat region including the larynx and the other one without it, are numerically investigated. The results revealed that the laryngeal jet has a considerable effect on particle deposition. The presence of laryngeal jet leads to 4-fold and 2-fold higher deposition efficiencies for inlet flow rates of 30 and 90 L/min, respectively
Mechanical Characterisation and Numerical Modelling of TPMS-Based Gyroid and Diamond Ti6Al4V Scaffolds for Bone Implants: An Integrated Approach for Translational Consideration
Additive manufacturing has been used to develop a variety of scaffold designs for clinical and industrial applications. Mechanical properties (i.e., compression, tension, bending, and torsion response) of these scaffolds are significantly important for load-bearing orthopaedic implants. In this study, we designed and additively manufactured porous metallic biomaterials based on two different types of triply periodic minimal surface structures (i.e., gyroid and diamond) that mimic the mechanical properties of bone, such as porosity, stiffness, and strength. Physical and mechanical properties, including compressive, tensile, bending, and torsional stiffness and strength of the developed scaffolds, were then characterised experimentally and numerically using finite element method. Sheet thickness was constant at 300 μm, and the unit cell size was varied to generate different pore sizes and porosities. Gyroid scaffolds had a pore size in the range of 600–1200 μm and a porosity in the range of 54–72%, respectively. Corresponding values for the diamond were 900–1500 μm and 56–70%. Both structure types were validated experimentally, and a wide range of mechanical properties (including stiffness and yield strength) were predicted using the finite element method. The stiffness and strength of both structures are comparable to that of cortical bone, hence reducing the risks of scaffold failure. The results demonstrate that the developed scaffolds mimic the physical and mechanical properties of cortical bone and can be suitable for bone replacement and orthopaedic implants. However, an optimal design should be chosen based on specific performance requirements. © 2022 by the authors.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]