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Scott, E. A.

Publications and source records attributed to Scott, E. A..

4 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Optical Manipulation of Vesicles for Optofluidic Applications

In this report, we review our recent results in the optical micromanipulation of vesicles. Traditionally, vesicle manipulation has been possible by employing photon momentum and optical trapping, giving rise to unique observations of vesicle shape changes and soft matter mechanics. Contrary to these attempts, we employ photon energy rather than momentum, by sensitizing vesicles with an oxidizing moiety. The later converts incident photons to reactive oxygen species, which in turn attack and compromise the stability of the vesicle membrane. Both coherent and incoherent radiation was employed. Polymersome re-organization into smaller diameter vesicles was possible by focusing the excitation beam in the vicinity of the polymersomes. Extended vesicle illumination with a collimated beam lead to their complete destabilization and micelle formation. Single particle analysis revealed that payload release takes place within seconds of illumination in an explosive burst. We will discuss the destabilization and payload release kinetics, as revealed by high resolution microscopy at the single particle level, as well as potential applications in single cell biomodulation.

Environmental Molecular Sciences Laboratory↗
DOE OSTI2013

Vesicle Photonics

Thin membranes, under appropriate boundary conditions, can self-assemble into vesicles, nanoscale bubbles that encapsulate and hence protect or transport molecular payloads. In this paper, we review the types and applications of light fields interacting with vesicles. By encapsulating light-emitting molecules (e.g. dyes, fluorescent proteins, or quantum dots), vesicles can act as particles and imaging agents. Vesicle imaging can take place also under second harmonic generation from vesicle membrane, as well as employing mass spectrometry. Light fields can also be employed to transport vesicles using optical tweezers (photon momentum) or directly pertrurbe the stability of vesicles and hence trigger the delivery of the encapsulated payload (photon energy).

Vasdekis, Andreas E.↗
NASA NTRS1990

Identification of aerospace acoustic sources using sparse distributed associative memory

A pattern recognition system has been developed to classify five different aerospace acoustic sources. In this paper the performance of two new classifiers, an associative memory classifier and a neural network classifier, is compared to the performance of a previously designed system. Sources are classified using features calculated from the time and frequency domain. Each classifier undergoes a training period where it learns to classify sources correctly based on a set of known sources. After training the classifier is tested with unknown sources. Results show that over 96 percent of sources were identified correctly with the new associative memory classifier. The neural network classifier identified over 81 percent of the sources correctly.

Scott, E. A.↗