Can the radiation pattern of an antenna be isotropic? A simple argument suggests that this is difficult. The intensity of radiation depends on the square of the electric (or magnetic) field. To have isotropic radiation, it would seem that the magnitude of the electric field would have to be uniform over any sphere in the far zone. However, the electromagnetic fields in the far zone of an antenn...

PURPOSE We sought to compare the ability of novice operators to provide artificial ventilation using a standard facemask and a new ergonomically designed facemask. Whether or not proper technique was used was also assessed. METHODS Thirty-two allied-health students used both masks in random crossover fashion to ventilate an airway trainer. Breaths were delivered by a mechanical ventilator and...

This paper describes the automated creation of a textured face mask of a natural person suitable for realtime animation. A 3D surface polygon face mask is used. A set of muscles is defined to animate the mask. The mask is adapted to a real person using 3D surface data from a calibrated stereo sensor. Firstly, the facial features of the mask are aligned to the 3D data by scaling the mask. Second...

background: cuffed pharyngeal tube is a device designed for ventilation of anesthetized patients. cpt has advantages over face mask including: maintaining of face mask can be difficult and boring after several minutes and mobility of the practitioner is reduced due to involvement of hands. mask pressure can cause soft tissue and nerve damage around the nose. anesthetic gas leakage from the mask...

The purpose of this study was to compare the effects of wearing different kinds of masks on the ear canal temperature, heart rate, clothing microclimate, and subjective perception of discomfort. Ten subjects performed intermittent exercise on a treadmill while wearing the protective masks in a climatic chamber controlled at an air temperature of 25 degrees C and a relative humidity of 70%. Two ...

To determine factors that predispose or protect healthcare workers from severe acute respiratory syndrome (SARS), we conducted a retrospective cohort study among 43 nurses who worked in two Toronto critical care units with SARS patients. Eight of 32 nurses who entered a SARS patient's room were infected. The probability of SARS infection was 6% per shift worked. Assisting during intubation, suc...

emissions from fossil fuel combustion pose a serious threat to public health and =pose the need for animproved monitoring of polycyclic aromatic hydrocarbons (pars), a major class of persistent organicpollutants. for this purpose the present study reports an investigation of the electronic structure of pyrene byuse of different chemical models we also made a comparison between different chemica...

Mask ventilation is lifesaving, especially in cases of difficult intubation. Many publications have offered distinct techniques for optimizing mask ventilation. This article reviews currently available difficult mask ventilation literature and theory. We divide difficult mask ventilation into 3 broad categories based on etiology: inadequate mask seal, increased airway resistance, and decreased ...