This study demonstrates a novel method of drug delivery to the posterior pole by using aerosolized nanoparticles that may be used in the gas phase of vitrectomy. Therapeutic applications include antimetabolites for modulation of proliferative vitreoretinopathy, antimicrobial agents for endophthalmitis, antiangiogenic compounds for vasoproliferative disorders, corticosteroid delivery, and other pharmacotherapies directed at the retina and choroid.

Public reporting burden for tids collection of Information Is estimated to average 1 hour per response, including t•e time for reviewing instructions, searching exisltng data souem, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection o informarmo, indudiug suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Repo!ts (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington. VA 22202-4302. Respondents Maould be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for telling It comply with a cotaction of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY)2 ABSTRACTVarious peculiar aspects of drop sizing in a dense sp'ay, using the phase Doppler technique, are considered. In order to ensure that only one drop exists in the probe volume at any given time, the laser beams need to be focused to a very small spot, such as 50 ,unm. This may lead to deviations from the normally assumed Gaussian beam optics on the transmitting side. Hence, theoretical estimates of the probe volume dimensions are not reliable and may lead to erroneous measurement of liquid volume flux. In this report, a method of experimentally qualifying the phase Doppler probe volume is described for accurate volume flux measurements.

A high (8 MHz) and low (1.7 MHz) frequency ultrasonic transducer were compared for delivering aerosols to mouse lung. The aerosol concentration (mass of dry particles/volume of air) rose nonlinearly with solution concentration of difluoromethyl ornithine for both transducers. The particle size was linear with the cube root of the solution concentration, and the slope of the low frequency transducer was eight times greater than that of the high frequency transducer. The deposition fraction assessed by the assayed mass in the lung relative to the calculated inhaled mass was found to decline exponentially with particle size. The lower frequency transducer provided a higher dose despite a lower deposition fraction, but the high frequency transducer was more efficient and provides a more selective deposition in the lower respiratory tract while operating with significantly less demands on aerosol drying.

technique is a non-intrusive optical device for in-situ measurement of single particles. In the case of an irregular particle, it provides a deterministic measure of particle velocity and statistical information about the particle size in the form of a phase shift signal. By collecting sufficient signals, velocity-resolved particle size distributions can be reconstructed. This is demonstrated by comparing phase Doppler measurements of irregular particles with an aerodynamic particle sizer. Preliminary measurements in a crystallizer are also presented. The present device is shown to work with near back-scatter collection of scattered light; hence, leads to a robust setup that can be used under the conditions of limited optical access.

A novel water-based condensation particle counter has been developed using a patented, single-flow mixing (SFM) condenser that permits a conventional thermal approach of using a hot saturator followed by a cold condenser to activate and grow particles for counting with an optical detector. A computational fluid dynamics (CFD) model of the internal flow, temperature, and vapor profiles was used to predict the effectiveness of the SFM condenser. Using the results from the CFD model, the counting efficiency was numerically calculated for pure water droplets, and the CPC cut-point (i.e., 50% counting efficiency) was predicted to be 8.3 nm. The experimental performance of the new CPC was measured with differential mobility analyzer-classified, monodisperse particles. The measured cut-points were 8.2 nm for Ag particles and 3.9 nm for NaCl particles. The reduction in the cut-point for NaCl is the result of a compound effect: water uptake by NaCl particles, which increases their size before entering into the growth section (condenser), and the reduction of the equilibrium vapor pressure of water over NaCl-water droplets, resulting in a decrease of the activation diameter.