Wake Vortex Attenuation Flight Tests: A Status Report

Flight tests were conducted to evaluate the magnitude of aerodynamic attenuation of the wake vortices of large transport aircraft that can be achieved through the use of static spoiler deflection and lateral control oscillation. These methods of attenuation were tested on Boeing B-747 and Lockheed L-1011 commercial transport aircraft. Evaluations were made using probe aircraft, photographic and visual observations, and ground based measurements of the vortex velocity profiles. The magnitude of attenuation resulting from static spoiler deflection was evaluated both in and out of ground effect. A remotely piloted QF-86 drone aircraft was used to probe the attenuated vortices in flight in and out of ground effect, and to make landings behind an attenuated B-747 airplane at reduced separation distances

Vortex attenuation flight experiments

Flight tests evaluating the effects of altered span loading, turbulence ingestion, combinations of mass and turbulence ingestion, and combinations of altered span loading turbulance ingestion on trailed wake vortex attenuation were conducted. Span loadings were altered in flight by varying the deflections of the inboard and outboard flaps on a B-747 aircraft. Turbulence ingestion was achieved in flight by mounting splines on a C-54G aircraft. Mass and turbulence ingestion was achieved in flight by varying the thrust on the B-747 aircraft. Combinations of altered span loading and turbulence ingestion were achieved in flight by installing a spoiler on a CV-990 aircraft and by deflecting the existing spoilers on a B-747 aircraft. The characteristics of the attenuated and unattenuated vortexes were determined by probing them with smaller aircraft. Acceptable separation distances for encounters with the attenuated and unattenuated vortexes are presented

Flight test investigation of the vortex wake characteristics behind a Boeing 727 during two-segment and normal ILS approaches (A joint NASA/FAA report)

Flight tests were performed to evaluate the vortex wake characteristics of a Boeing 727 aircraft during conventional and two-segment instrument landing approaches. Smoke generators were used for vortex marking. The vortex was intentionally intercepted by a Lear Jet and a Piper Comanche aircraft. The vortex location during landing approach was measured using a system of phototheodolites. The tests showed that at a given separation distance there are no readily apparent differences in the upsets resulting from deliberate vortex encounters during the two types of approaches. The effect of the aircraft configuration on the extent and severity of the vortices is discussed

Effect of cholesterol-poly(N,N-dimethylaminoethyl methacrylate) on the properties of stimuli-responsive polymer liposome complexes

The development of new polymer–liposome complexes (PLCs) as delivery systems is the key issue of this work. Three main areas are dealt with: polymer synthesis/characterization, liposome formulation/characterization and evaluation of the PLCs uptake by eukaryotic cells. Poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) with low molecular weight and narrow polydispersity was synthesized by Atom Transfer Radical Polymerization (ATRP). The polymers were synthesized using two different bromide initiators (cholesteryl-2-bromoisobutyrate and ethyl 2-bromoisobutyrate) as a route to afford PDMAEMA and CHO-PDMAEMA. Both synthesized polymers (PDMAEMA and CHO-PDMAEMA) were incorporated in the preparation of lecithin liposomes (LEC) to obtain PLCs. Three polymer/lipid ratios were investigated: 5, 10 and 20%. Physicochemical characterization of PLCs was carried out by determining the zeta potential, particle size distribution, and the release of fluorescent dyes (carboxyfluorescein CF and calcein) at different temperatures and pHs. The leakage experiments showed that CHO covalently bound to PDMAEMA strongly stabilizes PLCs. The incorporation of 5% CHO-PDMAEMA to LEC (LEC_CHO-PD5) appeared to be the stablest preparation at pH 7.0 and at 37 °C. LEC_CHO-PD5 destabilized upon slight changes in pH and temperature, supporting the potential use of CHO-PDMAEMA incorporated to lecithin liposomes (LEC_CHO-PDs) as stimuli-responsive systems. In vitro studies on Raw 264.7 and Caco-2/TC7 cells demonstrated an efficient incorporation of PLCs into the cells. No toxicity of the prepared PLCs was observed according to 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. These results substantiate the efficiency of CHO-PDMAEMA incorporated onto LEC to assist for the release of the liposome content in mildly acidic environments, like those found in early endosomes where pH is slightly lower than the physiologic. In summary, the main achievements of this work are: (a) novel synthesis of CHO-PDMAEMA by ATRP, (b) stabilization of LEC by incorporation of CHO-PDMAEMA at neutral pH and destabilization upon slight changes of pH, (c) efficient uptake of LEC_CHO-PDs by phagocytic and non-phagocytic eukaryotic cells.Facultad de Ciencias Exacta

Effect of cholesterol-poly(N,N-dimethylaminoethyl methacrylate) on the properties of stimuli-responsive polymer liposome complexes

The development of new polymer–liposome complexes (PLCs) as delivery systems is the key issue of this work. Three main areas are dealt with: polymer synthesis/characterization, liposome formulation/characterization and evaluation of the PLCs uptake by eukaryotic cells. Poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) with low molecular weight and narrow polydispersity was synthesized by Atom Transfer Radical Polymerization (ATRP). The polymers were synthesized using two different bromide initiators (cholesteryl-2-bromoisobutyrate and ethyl 2- bromoisobutyrate) as a route to afford PDMAEMA and CHO-PDMAEMA. Both synthesized polymers (PDMAEMA and CHO-PDMAEMA) were incorporated in the preparation of lecithin liposomes (LEC) to obtain PLCs. Three polymer/lipid ratios were investigated: 5, 10 and 20%. Physicochemical characterization of PLCs was carried out by determining the zeta potential, particle size distribution, and the release of fluorescent dyes (carboxyfluorescein CF and calcein) at different temperatures and pHs. The leakage experiments showed that CHO covalently bound to PDMAEMA strongly stabilizes PLCs. The incorporation of 5% CHO-PDMAEMA to LEC (LEC CHO-PD5) appeared to be the stablest preparation at pH 7.0 and at 37 ◦C. LEC CHO-PD5 destabilized upon slight changes in pH and temperature, supporting the potential use of CHO-PDMAEMA incorporated to lecithin liposomes (LEC CHO-PDs) as stimuli-responsive systems. In vitro studies on Raw 264.7 and Caco-2/TC7 cells demonstrated an efficient incorporation of PLCs into the cells. No toxicity of the prepared PLCs was observed according to 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) assays. These results substantiate the efficiency of CHO-PDMAEMA incorporated onto LEC to assist for the release of the liposome content in mildly acidic environments, like those found in early endosomes where pH is slightly lower than the physiologic. In summary, the main achievements of this work are: (a) novel synthesis of CHO-PDMAEMA by ATRP, (b) stabilization of LEC by incorporation of CHO-PDMAEMA at neutral pH and destabilization upon slight changes of pH, (c) efficient uptake of LEC CHO-PDs by phagocytic and non-phagocytic eukaryotic cells.Fil: Alves, P.. Universidad de Coimbra; PortugalFil: Hugo, Ayelen Amelia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Investigaciones en Criotecnología de Alimentos (i); Argentina. Universidad Nacional de La Plata; ArgentinaFil: Tymczyszyn, Emma Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Investigaciones en Criotecnología de Alimentos (i); Argentina. Universidad Nacional de La Plata; ArgentinaFil: Ferreira, A. F. . Universidad de Coimbra; PortugalFil: Fausto, R.. Universidad de Coimbra; PortugalFil: Perez, Pablo Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Investigaciones en Criotecnología de Alimentos (i); Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biologicas; ArgentinaFil: Coelho, J. F. J.. Universidad de Coimbra; PortugalFil: Simões, P. N.. Universidad de Coimbra; PortugalFil: Gomez Zavaglia, Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Investigaciones en Criotecnología de Alimentos (i); Argentina. Universidad Nacional de La Plata; Argentin

Gas-Phase Energetics of Organic Free Radicals using Time-Resolved Photoacoustic Calorimetry

The development of new polymer-liposome complexes (PLCs) as delivery systems is the key issue of this work. Three main areas are dealt with: polymer synthesis/characterization, liposome formulation/characterization and evaluation of the PLCs uptake by eukaryotic cells. Poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) with low molecular weight and narrow polydispersity was synthesized by Atom Transfer Radical Polymerization (ATRP). The polymers were synthesized using two different bromide initiators (cholesteryl-2-bromoisobutyrate and ethyl 2-bromoisobutyrate) as a route to afford PDMAEMA and CHO-PDMAEMA. Both synthesized polymers (PDMAEMA and CHO-PDMAEMA) were incorporated in the preparation of lecithin liposomes (LEC) to obtain PLCs. Three polymer/lipid ratios were investigated: 5, 10 and 20%. Physicochemical characterization of PLCs was carried out by determining the zeta potential, particle size distribution, and the release of fluorescent dyes (carboxyfluorescein CF and calcein) at different temperatures and pHs. The leakage experiments showed that CHO covalently bound to PDMAEMA strongly stabilizes PLCs. The incorporation of 5% CHO-PDMAEMA to LEC (LEC_CHO-PD5) appeared to be the stablest preparation at pH 7.0 and at 37°C. LEC_CHO-PD5 destabilized upon slight changes in pH and temperature, supporting the potential use of CHO-PDMAEMA incorporated to lecithin liposomes (LEC_CHO-PDs) as stimuli-responsive systems. In vitro studies on Raw 264.7 and Caco-2/TC7 cells demonstrated an efficient incorporation of PLCs into the cells. No toxicity of the prepared PLCs was observed according to 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. These results substantiate the efficiency of CHO-PDMAEMA incorporated onto LEC to assist for the release of the liposome content in mildly acidic environments, like those found in early endosomes where pH is slightly lower than the physiologic. In summary, the main achievements of this work are: (a) novel synthesis of CHO-PDMAEMA by ATRP, (b) stabilization of LEC by incorporation of CHO-PDMAEMA at neutral pH and destabilization upon slight changes of pH, (c) efficient uptake of LEC_CHO-PDs by phagocytic and non-phagocytic eukaryotic cells