Showing 3 results for Respiratory System
Ali Reza Tahavvor, Pouya Zarrinchang, Shahin Heidari,
Volume 14, Issue 15 (3-2015)
Abstract
The nose and nasal cavity and sinuses are a parts of the upper respiratory system and study the air passage into the upper component of human airway is important to improve or cure deficiency in human respiration cycle. The nose performs many important physiological functions, including heating, humidifying and filtering inspired air, as well as sampling air to smell. Previously, numerical modeling of turbulent flow in nasal cavity, sinus, pharynx and larynx has rarely been employed Since the 1990s, with the development of computed tomography technology and computational fluid dynamics, a number of numerical studies on gas and particle flows in realistic nasal cavities have been conducted and provided precise data for deeper insight of the nature of nasal airflows. Also, most of pioneering studies in this field have been developed to the investigation of only nasal cavity without sinuses especially maxillary sinus So, this research is tried to study details of turbulent airflow through all spaces in human head that air can flow through. For this purpose, study has based on computed tomography scans image of a 26-years old female head, neck and chest without problems in her respiratory system from Shahid Chamran hospital, Shiraz, Iran. It is found that, nasal resistance was contribute up to half of the total airway resistance within the first 2-3 cm of the airway and the majority of the flow in this region remained close to the septum wall and only a small proportion reached the olfactory region.
N. Parsa Mofrad, M.m. Tavakol ,
Volume 19, Issue 4 (4-2019)
Abstract
In this paper, the effect of a mannequin location with an integrated respiratory system in a ventilated room on the flow field and particle dispersion was evaluated, using numerical simulations. Dispersion and deposition of particles inside the respiratory system and inside the room have been investigated, using a Lagrangian approach. The respiratory system contains the nasal airway, nasopharynx, oropharynx, and larynx, trachea, which has been generated from CT scan images and installed on a 3D mannequin model. The evaluation conditions varied as standing and sleeping mannequins form in a room that includes 2 input dampers and 4 output dampers. For simulation of the flow field, the ANSYS FLUENT software- version 17.2 with the 4-equation SST transition turbulence model have been used. Simulations have been performed for 3 different respiration flow rates and 4 different particle diameters. Results indicate higher deposition on the sleeping model rather than standing model due to gravitational effect. The total aspiration of particles inside the respiratory system was less than 0.4%. In addition, the nasal cavity captures large particles, while for small particles, higher deposition occurs in the lower parts of the respiratory tract.
Volume 27, Issue 2 (11-2024)
Abstract
Background: Harmaline exhibits a diverse array of pharmacological properties, including antimicrobial, antidiabetic, osteogenic, immunomodulatory, emmenagogue, and antitumor activities. The current study aimed to investigating the effect of harmaline on oxidative stress factors in lung epithelial cells exposed to elastase. Material and method: oxidative stress markers of lung epithelial cells were investigated in all cell groups including, control, H2O2, elastase and elastase plus harmaline (50, 100, 200 μm). lung epithelial cells (A549) were exposed to elastase with concentrations of 60 U/ml for 24 hours. In other groups, cells exposed to elastase were co-treated with three different doses of harmaline (50, 100 and 200 µm) for 24 hours at 37°C. Results: the results show a significant effect of harmaline's protective effect on cell viability, free radical production (ROS), malondialdehyde (MDA) and total antioxidant capacity (TAC). harmaline significantly increased the viability and TAC level in the cells exposed to elastase. Also, harmaline significantly decreased the percentage of free radicals and the MDA level in the cells exposed to elastase. Conclusion: The results obtained from this study showed a significant protective effect of harmaline on cell viability through increases in antioxidant defense system. Therefore, harmaline, can probably considered as a therapeutic strategy to prevent or treatment of lung diseases.
