BACKGROUND A common auscultatory finding in pulmonary emphysema is a reduction of lung sounds. This might be due to a reduction in the generation of sounds due to the accompanying airflow limitation or to poor transmission of sounds due to destruction of parenchyma. Lung sound intensity was investigated in normal and emphysematous subjects in relation to airflow. METHODS Eight normal men (45-...

BACKGROUND Both airflow limitation and obstructive sleep apnea-hypopnea syndrome (OSAHS)-related symptoms are most prevalent in the elderly population. Previous studies revealed significant associations between OSAHS-related symptoms and obstructive airway diseases in the general population. However, other studies showed that the frequency of OSAHS-related symptoms in patients with obstructive ...

BACKGROUND Chronic obstructive pulmonary disease is caused mainly by habitual smoking and is common among elderly individuals. It involves not only airflow limitation but also metabolic disorders, leading to increased cardiovascular morbidity and mortality. OBJECTIVE We evaluated relationships among smoking habits, airflow limitation, and metabolic abnormalities. METHODS Between 2001 and 20...

Airflow along rivers might provide a key mechanism for ventilation in cities: important for air quality and thermal comfort. Airflow varies in space and time in the vicinity of rivers. Consequently, there is limited utility in point measurements. Ground-based remote sensing offers the opportunity to study 3D airflow in locations which are difficult to observe with conventional approaches. For t...

The use of a scaled model can be an effective technique to predict ventilation performance of full-scale prototypes. Many criteria have been proposed to predict the behavior of airflow in a scale model and a prototype. Because of inconsistent results of proposed similarity criteria, more validation work is needed to clarify the conflicts. Experiments to study airflow similarity in ceiling slot-...

TWO unique models, the Lam-Bremhorst low Reynolds number turbulence model (LBLR) and a multiple airflow regions model (MARM), were compared in describing the distribution of carbon dioxide (CO2) in a simulated swine grower pen used in a previous experimental study (Brannigan and McQuitty, 1971), The results from this comparative study indicate that the LBLR model's ability to predict airflow pa...

This study investigates the pressure-drop behaviour associated with airflow through bulk and structurally tailored multi-layered, open-cell porous Inconel structures over a wide airflow velocity range (0-50 m s). The effect of airflow velocity on the pressure-drop behaviour as a function of the sample thickness is presented and related to the flow behaviour corresponding to the relevant flow re...

The timing and magnitude of airway narrowing in central apneas is unknown. We have developed a method of apnea classification that relies on the transmission of cardiac airflow oscillation to indicate airway patency. Using a theoretical model, we showed that the amplitude of the cardiac airflow oscillation is proportional to airway diameter for small lumens. While in the majority of central apn...

The airflow in the modeled glottal constriction was simulated by the solutions of the Navier-Stokes equations for laminar flow, and the corresponding Reynolds equations for turbulent flow in generalized, nonorthogonal coordinates using a numerical method. A two-dimensional model of laryngeal flow is considered and aerodynamic properties are calculated for both laminar and turbulent steady flows...