Lack of coordination between the beginning of the inhalation and device triggering is one of the most frequent errors reported in connection with the use of pMDI devices. Earlier results suggested a significant loss in lung deposition as a consequence of late actuation. However, most of our knowledge on the effect of poor synchronization is based on earlier works on CFC devices emitting large particles with high initial velocities. The aim of this study was to apply numerical techniques to analyse the effect of late device actuation on the lung dose of a HFA pMDI drug emitting high fraction of extrafine particles used in current asthma and COPD therapy. A computational fluid and particle dynamics model was combined with stochastic whole lung model to quantify the amount of drug depositing in the extrathoracic airways and in the lungs. High speed camera measurements were also performed to characterize the emitted spray plume. Our results have shown that for the studied pMDI drug late actuation leads to reasonable loss in terms of lung dose, unless it happens in the second half of the inhalation period. Device actuation at the middle of the inhalation caused less than 25% lung dose reduction relative to the value characterizing perfect coordination, if the inhalation time was between 2 and 5 s and inhalation flow rate between 30 and 150 L/min. This dose loss is lower than the previously known values of CFC devices and further support the practice of triggering the device shortly after the beginning of the inhalation instead of forcing a perfect synchronization and risking mishandling and poor drug deposition.
The authors present two cases of newborn babies infected by Trichomonas vaginalis (hereafter referred to as T. vaginalis) and suffering from severe congenital breathing difficulties and needing artificial respiration. Microscopic examination of the tracheal discharge revealed characteristically moving, flagellated, pear-shaped unicellular organisms. Cultures on CPLM medium proved the presence of T. vaginalis. During pregnancy the mothers' clinical status was negative and both of them mentioned leukorrhoea of changing intensity. They were regularly involved in antenatal care. The infection caused by T. vaginalis could be detected in the two mothers later by culture procedures.
A new sort of thermoluminescent phosphor has been developed with the purpose of enlarging the range of linear dose-response. The thermoluminescence properties of CaSO(4):Tm,Cu, prepared according to our method, were studied in the dose range of 0.5 Gy-125.0 kGy. The results of the present work show that the CaSO(4):Tm,Cu is an excellent new dosimetric material due to its relatively simple glow curve, as a consequence of its simple trap system. Several applications are possible in dosimetry due to its wide range of linearity (2 x 10(-6) to 2 x 10(3) Gy), from environmental and space dosimetry to accidental and high-dose irradiation, e.g. gamma irradiation facilities, electron accelerators, nuclear power plants, radiotherapy, medical physics, and so on.
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