Aerosol drug delivery/deposition in human lungs. — An optical measurement method based on laser particle counting has been developed, which can be used as a replacement of the commonly used analytical methods. A new procedure was developed based on optical image processing for the determination of the amount of deposited particles on the catch plates of cascade impactors. We utilized this method for the investigation of the effect of the humidity on the size distribution of the inhaled drug particles.
A measurement setup was built and utilized to study the temporal development of the size distribution of the generated mist of pressurized metered dose inhalers (pMDI) which influence the spatial deposition distribution of the particles in the human airways. While the pump with the flow controller generates constant flow rate in a closed loop, the breath simulator and the mixing inlet ensures realistic breathing patterns at the pMDI device. An optical particle counter (OPC) isokinetically samples particles from the main flow providing the necessary dilution to avoid coincidence of particles in the measurement volume caused by the high concentration. Measurements were performed to determine the temporal variation of the size distribution of the aerosols generated by pMDI devices and also studied the effects of the synchronization problems commonly raised during the usage of these devices.
All of the above mentioned methods have their own advantages in terms of speed and sensitivity of the measurement. The established theoretical and experimental background and the elaborated methods and tools can be used widely not only for the investigation of aerosol drug delivery, but for studying the deposition properties of natural and toxic aerosols as well.
Study of optical properties of aerosols. — Optical aerosol instrumentation was utilized to identify the sources of aerosol contamination in the air of Budapest. The results of the size distribution and absorptivity measurements show clear correlation with weather conditions, indicating the differences between the locations in the neighbourhoods.
Optical thin-film structures consisting of nanoscale laminated layers. – We have continued our research towards the development of optical thin-film structures containing nanooptically thin layers for advanced applications in laser physics and information technology.
EXMET – Interferometric measurement methods. — The Michelson-type interferometer which was developed in the previous phase of this project was utilized for plasma diagnostics. The properties of the plasma generated in rubidium vapors by intense femtosecond laser pulses were studied using interferometry scheme in coaxial arrangement with the ionizing laser beam (Fig. 1.). This method was found to be a useful tool for laser plasma diagnostics and may complement the absorption spectroscopy methods. It can be even utilized with laser sources that produce less intense measuring beam because of the intrinsic nature of interferometry.
Figure 1. Schematic measurement setup for studying the dynamics of an Rb plasma generated by ultra-short laser pulses
Development of an imaging optical inspection device with a pinhole camera. – In cooperation with the Institute of Technical Physics and Material Sciences of Centre for Energy Research, an upgraded version of our “Imaging Optical Inspection Device With A Pinhole Camera” was developed. The aim was to increase the size of the measurable targets. It requires a significant increase of brightness of the special „point like” light source, the speed and range of precisely controlled target movement, and data processing. The unit was successfully installed in the clean-room of IISB (Erlangen, Germany). (For details see: http://www.ellipsometry.hu/)
Service laboratory for optical measurements. — We have continued the utilization of our surface profiler based on white light interferometry. We have performed aerosol measurements by optical and spectroscopic methods in the frame of academic cooperations and industrial contracts.