Creation of Light Scattering Images in a Polymer Film by Quantum Amplified Isomerization

The quantum amplified, photosensitized isomerization of a Dewar benzene reactant to a benzene product was used to create a visible image based on differential light scattering. The reactant and a UV triplet sensitizer were dispersed together as small particles in a solid, continuous matrix of gelatin, coated on a polyester film support. The refractive indexes of the particulate and continuous phases were initially approximately matched, leading to an essentially transparent appearance. After exposure to UV light (absorbed by the sensitizer), the change in refractive index resulting from the isomerization caused a significant mismatch in refractive index between the particles and the binder. In addition, the product partially crystallized. The outcome was an opaque texture in the coating. A pictorial image attributable to regions of high and low light scattering could be prepared by irradiation of the coating through a simple contact mask. The scattering texture forms spontaneously on irradiation, without any chemical processing or heating. The image is indefinitely stable in the absence of heat and UV light

Quantum Amplified Isomerization: A New Chemically Amplified Imaging System in Solid Polymers

A new imaging system based on a photoinitiated electron transfer chain reaction is reported. Specifically, irradiation of 9,10-dicyanoanthracene (sensitizer) leads to the conversion of Dewar benzene derivatives (reactants) to benzene derivatives (products) within solid polymer films. The mechanism of the reaction may involve chemical amplification with cation radicals ( holes ) as the catalytic species. We present herein studies of both molecularly doped polymers and polymers containing Dewar benzene moieties attached to side chains. The refractive index of the materials could be tuned within a narrow range using this photochemical reaction, as demonstrated by the writing of persistent gratings in forced Rayleigh scattering experiments

The role of GABAA receptors in the acute and chronic effects of ethanol: a decade of progress

The past decade has brought many advances in our understanding of GABA(A) receptor-mediated ethanol action in the central nervous system. We now know that specific GABA(A) receptor subtypes are sensitive to ethanol at doses attained during social drinking while other subtypes respond to ethanol at doses attained by severe intoxication. Furthermore, ethanol increases GABAergic neurotransmission through indirect effects, including the elevation of endogenous GABAergic neuroactive steroids, presynaptic release of GABA, and dephosphorylation of GABA(A) receptors promoting increases in GABA sensitivity. Ethanol’s effects on intracellular signaling also influence GABAergic transmission in multiple ways that vary across brain regions and cell types. The effects of chronic ethanol administration are influenced by adaptations in GABA(A) receptor function, expression, trafficking, and subcellular localization that contribute to ethanol tolerance, dependence, and withdrawal hyperexcitability. Adolescents exhibit altered sensitivity to ethanol actions, the tendency for higher drinking and longer lasting GABAergic adaptations to chronic ethanol administration. The elucidation of the mechanisms that underlie adaptations to ethanol exposure are leading to a better understanding of the regulation of inhibitory transmission and new targets for therapies to support recovery from ethanol withdrawal and alcoholism