Search results for " light"
showing 10 items of 1141 documents
Tuning size and thermal hysteresis in bistable spin crossover nanoparticles.
2010
Nanoparticles of iron(II) triazole salts have been prepared from water-organic microemulsions. The mean size of the nanoparticles can be tuned down to 6 nm in diameter, with a narrow size distribution. A sharp spin transition from the low spin (LS) to the high spin (HS) state is observed above room temperature, with a 30-40-K-wide thermal hysteresis. The same preparation can yield second generation nanoparticles containing molecular alloys by mixing triazole with triazole derivatives, or from metallic mixtures of iron(II) and zinc(II). In these nanoparticles of 10-15 nm, the spin transition "moves" towards lower temperatures, reaching a 316 K limit for the cooling down transition and mainta…
Optical retarder system with programmable spectral retardance.
2014
An optical system that works as a retarder waveplate with programmable spectral retardance is proposed. The system is based on a pixelated liquid crystal on silicon (LCoS) spatial light modulator (SLM). The input light beam is spectrally dispersed and different spectral components are projected onto different pixels of the LCoS-SLM. A different retardance is then addressed for each pixel, adapted to the incoming wavelength. Light reflected from the SLM is then recombined by the same setup. In this way a programmable polarization spectrum can be encoded. We illustrate the broadband characterization that is required for proper use of the system. Then several examples are shown, including spec…
Nylon-Supported Plasmonic Assay Based on the Aggregation of Silver Nanoparticles: In Situ Determination of Hydrogen Sulfide-like Compounds in Breath …
2019
A procedure for supporting silver nanoparticles (AgNPs) on nylon is proposed. Besides, the membrane has been developed as a solid-phase colorimetric plasmonic sensor for volatile sulfide compounds (VSCs) like H2S, CH3SH, and (CH3)2S. AgNP behavior in the membrane has been studied by UV-vis diffuse reflectance spectrometry, Raman spectrometry, High-resolution transmission electron microscopy (HR-TEM), and Scanning electron microscopy (SEM). The sensor responded by changing its color from yellow in absence of VSCs to several orange/brown colors in the function of VSC concentration as occurs in solution; an increase in the hydrodynamic diameter, estimated by both asymmetrical flow field-flow f…
Selective aqueous oxidation of aromatic alcohols under solar light in the presence of TiO2 modified with different metal species
2022
AbstractA set of metals modified TiO2 photocatalysts were prepared starting from titanium tetraisopropoxyde and different metal precursors to study the influence of the addition of the various foreign agents on the physico-chemical and photocatalytic properties of the catalysts. The powders were characterized by X-ray diffraction, Raman spectroscopy, specific surface area measurements, scanning electron microscopy, energy dispersive X-ray spectroscopy, UV–Vis diffuse reflectance spectroscopy, photoluminescence, temperature programmed desorption after CO2 adsorption. The photocatalytic activity was evaluated using as probe reactions the partial oxidation of three aromatic alcohols: benzyl al…
Fiat lux: the light became therapy. An overview on the Bright Light Therapy in Alzheimer’s Disease sleep disorders
2020
Background: A system of photosensitive retinal ganglion cells provides ‘non-visual’ information on the circadian sequences of light to the suprachiasmatic nucleus (SCN), which, as the ‘master clock’, synchronizes the chronobiological mechanisms of all the biological clocks. Damage to SCN structure alters circadian behavioral and hormonal rhythms and interferes with a regular sleep-wake pattern. Several studies have shown that, in aging and in Alzheimer’s disease (AD), circadian rhythms change their synchronization with the environment and behavior loses sync with light. Objective: The current overview aims to examine research studies showing the effect of bright light therapy (BLT) on sleep…
Circulating tumor and immune cells for minimally invasive risk stratification of smoldering multiple myeloma
2022
Abstract Purpose: Early intervention in smoldering multiple myeloma (SMM) requires optimal risk stratification to avoid under- and overtreatment. We hypothesized that replacing bone marrow (BM) plasma cells (PC) for circulating tumor cells (CTC), and adding immune biomarkers in peripheral blood (PB) for the identification of patients at risk of progression due to lost immune surveillance, could improve the International Myeloma Working Group 20/2/20 model. Experimental Design: We report the outcomes of 150 patients with SMM enrolled in the iMMunocell study, in which serial assessment of tumor and immune cells in PB was performed every 6 months for a period of 3 years since enrollment. Resul…
Lutter contre la pollution lumineuse
2019
La dégradation de l’obscurité sous l’effet des usages de lumière artificielle nocturne dans et aux abords des infrastructures humaines est appelée pollution lumineuse. Liée à l’urbanisation, cette pollution déborde les espaces urbains pour affecter les espaces ruraux et les aires protégées. La lutte contre la pollution lumineuse s’organise dans plusieurs pays, dans lesquels des territoires expérimentent des politiques environnementales de protection de l’obscurité. L’enjeu porte à la fois sur la préservation de la biodiversité et la transition énergétiques. En France, quelques territoires ruraux pionniers expérimentent des dispositifs intégrant ce double enjeu. Deux d’entre eux constituent …
“Out of Sight, Out of Mind?”: The Role of Physical Stressors, Cognitive Appraisal, and Positive Emotions in Employees’ Health
2017
This study analyzes the mediating role of the appraisal of environmental stressors in the relationship between physical characteristics in the offices and health symptoms. It also studies the moderating role of positive emotions in the relationship between physical characteristics and the appraisal of environmental stressors using a diary study on 59 office workers ( n = 432 time points) and sensor data. The results show that the appraisal of environmental stressors mediates the relationship between physical office characteristics and health symptoms, emphasizing the important link of stress appraisal in the stressors–strain relationship. The results also show that positive emotions modera…
Two-year retrospective analysis of the international impact of Journal of Optometry: part II
2011
The Journal of Optometry – Peer-reviewed Journal of the Spanish General Council of Optometrists- was launched in March 2008 publishing the first issue by September 2008. It is now reaching 2.5 years of activity in spreading clinical and scientific knowledge in the field of Optometry and Visual Science and related areas. Despite this short path within the international scientific publication scenario, it is appropriate to stop and reflect about the challenges, achievements and the numbers that are making J Optom a reference in this competitive area. In this editorial we will discuss the steps followed to setup the journal and the actual international impact in terms of audience from the read…
Modulating the luminance of organic light-emitting diodes via optical stimulation of a photochromic molecular monolayer at transparent oxide electrode
2020
Nanoscale 12(9), 5444-5451 (2020). doi:10.1039/D0NR00724B