Search results for "photor"

Multiplexing of encrypted data using fractal masks

2012

In this Letter, we present to the best of our knowledge a new all-optical technique for multiple-image encryption and multiplexing, based on fractal encrypting masks. The optical architecture is a joint transform correlator. The multiplexed encrypted data are stored in a photorefractive crystal. The fractal parameters of the key can be easily tuned to lead to a multiplexing operation without cross talk effects. Experimental results that support the potential of the method are presented.

Theoretical study of spiropyran-merocyanine thermal isomerization.

2004

Abstract Quantum mechanical computations at DFT level were carried out on the processes involved in the thermal reaction SP ⇆ ME, where SP is the nitro-substituted spirobenzopyran (1 ′ ,3 ′ -dihydro-1 ′ ,3 ′ ,3 ′ -trimethyl-6-nitro-spiro[2H-1-benzopyran-2,2 ′ - [2H]indole]) in the closed form and ME is the corresponding open form. A detailed theoretical description of the overall reaction is reported along with the thermodynamic parameters for all intermediates and transition states. The obtained activation energy value is in agreement with the available experimental data in solution.

Phenotypic Heterogeneity of the Insect Pathogen Photorhabdus luminescens: Insights into the Fate of Secondary Cells

2019

Photorhabdus luminescens is a Gram-negative bacterium that lives in symbiosis with soil nematodes and is simultaneously highly pathogenic toward insects. The bacteria exist in two phenotypically different forms, designated primary (1°) and secondary (2°) cells. Yet unknown environmental stimuli as well as global stress conditions induce phenotypic switching of up to 50% of 1° cells to 2° cells. An important difference between the two phenotypic forms is that 2° cells are unable to live in symbiosis with nematodes and are therefore believed to remain in the soil after a successful infection cycle. In this work, we performed a transcriptomic analysis to highlight and better understand the rol…

Radical addition to iminium ions and cationic heterocycles

2014

Carbon-centered radicals represent highly useful reactive intermediates in organic synthesis. Their nucleophilic character is reflected by fast additions to electron deficient C=X double bonds as present in iminium ions or cationic heterocycles. This review covers diverse reactions of preformed or in situ-generated cationic substrates with various types of C-radicals, including alkyl, alkoxyalkyl, trifluoromethyl, aryl, acyl, carbamoyl, and alkoxycarbonyl species. Despite its high reactivity, the strong interaction of the radical’s SOMO with the LUMO of the cation frequently results in a high regioselectivity. Intra- and intermolecular processes such as the Minisci reaction, the Porta react…

Incoherent solitons and condensation processes

2006

International audience; We study the nonlinear interaction of partially incoherent nonlinear optical waves. We show that, in spite of the incoherence of the waves, coherent phase effects may play a relevant role during the propagation, in contrast with the usual wave turbulence description of the interaction. These nonlinear phase effects may lead the system to unexpected processes of self-organization, such as condensation, or incoherent soliton generation in instantaneous response nonlinear media. Such self-organization processes may be characterized by a reduction of the non-equilibrium entropy, which violates the Boltzmann's H-theorem of entropy growth inherent to the wave turbulence th…

Corneal thickness differences between type 2 diabetes and non-diabetes subjects during preoperative laser surgery examination

2016

Aims To evaluate the differences in corneal thickness between type 2 diabetes subjects with HbA1c under 7.0% and non-diabetes subjects during their preoperative laser surgery examinations. Methods The mean of five consecutive corneal thickness measurements at the central and mid-peripheral cornea was obtained by means of noncontact scanning-slit corneal topography (Orbscan Topography System II; Orbscan, Inc., Salt Lake City, UT, USA) in 35 myopic non-insulin dependent type 2 diabetes subjects (17 males and 18 females) and 48 healthy myopic controls (23 males and 25 females). Results The corneal thickness values at the central and mid-peripheral cornea were significantly higher in the diabet…

Incisional Keratotomy to Toric Intraocular Lenses: An Overview of the Correction of Astigmatism in Cataract and Refractive Surgery

2003

Visible-light photoredox catalyzed synthesis of pyrroloisoquinolines via organocatalytic oxidation/[3 + 2] cycloaddition/oxidative aromatization reac…

2014

Beilstein journal of organic chemistry 10, 1233-1238 (2014). doi:10.3762/bjoc.10.122

Indoor artificial lighting: Prediction of the circadian effects of different spectral power distributions.

2014

The study presented in this paper aims to evaluate if and how the environment affects the circadian impact of a light source by predicting circadian stimulus (CS) resulting from the exposure to different light scenes, using equations reported in studies by Rea et al. The main findings are: (1) Above 600 lx at eye level the increase of CS is little; (2) Between 50 lx and 200 lx at the eye level an increase of only 50 lx determines a significant increase of CS; (3) Light sources with correlated colour temperatures between 2900 K and 4200 K have similar impacts on the circadian system according to the calculation method used; (4) Even an almost neutral environment affects the circadian impact…

The measurement of light transmission through an irradiated fluidised bed

1983

Abstract The transmission of light through an irradiated fluidised bed with vertical flat walls containing catalytic particles has been experimentally studied. The amount of light transmitted through the reactor was measured at different levels by a photocell. The experimental variables studied included: (i) gas flow rate, varying from 2 to more than 10 times that required for minimum fluidisation; (ii) mean particle size, ranging from 0.138 to 0.275 mm; and (iii) internal bed thickness from 2.1 to 4.9 mm. The effect of the reflectance of the particles was also examined. Results show that the amount of light transmitted through a flat fluidised bed is low. The average transmitted light has …