Wright-Patterson Air Force Base

About: Wright-Patterson Air Force Base is a other organization based out in Wright-Patterson AFB, Ohio, United States. It is known for research contribution in the topics: Laser & Microstructure. The organization has 5817 authors who have published 9157 publications receiving 292559 citations. The organization is also known as: Wright-Patterson AFB & FFO.

Towards understanding mechanisms governing cytotoxicity of metal oxides nanoparticles: hints from nano-QSAR studies.

Abstract: The production of nanomaterials increases every year exponentially and therefore the probability these novel materials that they could cause adverse outcomes for human health and the environment also expands rapidly. We proposed two types of mechanisms of toxic action that are collectively applied in a nano-QSAR model, which provides governance over the toxicity of metal oxide nanoparticles to the human keratinocyte cell line (HaCaT). The combined experimental–theoretical studies allowed the development of an interpretative nano-QSAR model describing the toxicity of 18 nano-metal oxides to the HaCaT cell line, which is a common in vitro model for keratinocyte response during toxic dermal exposure. The comparison of the toxicity of metal oxide nanoparticles to bacteria Escherichia coli (prokaryotic system) and a human keratinocyte cell line (eukaryotic system), resulted in the hypothesis that different modes of toxic action occur between prokaryotic and eukaryotic systems.

Mechanochromic Photonic Gels

Abstract: Polymer gels are remarkable materials with physical structures that can adapt significantly and quite rapidly with changes in the local environment, such as temperature, light intensity, electrochemistry, and mechanical force An interesting phenomenon observed in certain polymer gel systems is mechanochromism - a change in color due to a mechanical deformation Mechanochromic photonic gels are periodically structured gels engineered with a photonic stopband that can be tuned by mechanical forces to reflect specific colors These materials have potential as mechanochromic sensors because both the mechanical and optical properties are highly tailorable via incorporation of diluents, solvents, nanoparticles, or polymers, or the application of stimuli such as temperature, pH, or electric or strain fields Recent advances in photonic gels that display strain-dependent optical properties are discussed In particular, this discussion focuses primarily on polymer-based photonic gels that are directly or indirectly fabricated via self-assembly, as these materials are promising soft material platforms for scalable mechanochromic sensors

Nonlinear optical properties of a new chromophore

Abstract: Strong two-photon-absorption (TPA) based nonlinear optical properties of a new chromophore, N, N-diphenyl-7-[2-(4-pyridinyl) ethenyl]-9,9-di-n-decyl-fluoren-2-amine (AF-50) has been experimentally studied. Under excitation with 10-Hz, ∼8-ns, and ∼800-nm laser pulses, the TPA cross section and the TPA-induced frequency-upconverted emission spectra are measured for AF-50 solutions in various solvents. The most attractive feature of this chromophore is its remarkably high value of the molecular TPA cross section (∼78×10-20 cm2/GW in benzene solution). Based on this feature, superior optical power limiting and stabilization performance has been demonstrated in a 1-cm-long AF-50 solution sample with concentration of d0=0.045 M/L. The nonlinear transmission of the measured sample decreased from ∼0.93 to ∼0.3 when the input-beam intensity increased from ∼10 MW/cm2 to ∼360 MW/cm2; the relative intensity fluctuation of the output laser pulses was reduced to one third of that of the input laser beam.