Search results for "eye"
showing 10 items of 2511 documents
Structure and phase transitions of a liquid crystalline polymer
1981
The structures, textures as well as thermodynamic properties of a side chain polymer exhibiting a liquid crystalline phase in addition to a partially crystalline state and the isotropic fluid state were investigated. Furthermore the kinetics of phase transitions between these states were analyzed. It was found that the properties of this polymer are intermediate between that of low molecular weight liquid crystals and common polymers. In particular it was observed that the relation between the liquid crystalline texture and the structure is different from that of low molecular weight liquid crystals and that the properties of the crystalline and liquid crystalline state depend strongly on t…
Phase Behaviour of Dye-Containing Liquid Crystalline Copolymers and their Mixtures with Low Molecular Weight Liquid Crystals
1985
Liquid crystalline side-chain polymers can be obtained by connecting the mesogenic groups and the polymer chain via a flexible spacer. The liquid crystalline polymers combine the well-known properties of low molecular weight liquid crystals with those of polymers.1
NonclassicalPschorr andSandmeyer Reactions in Pyrazole Series
2005
The diazonium salt derived from 4-amino-N,1,3-trimethyl-N-(3-methyl-1-phenyl-1H-pyrazol-5-yl)-1H-pyrazole-5-carboxamide (14) was reacted with a mixture of CuSO4 and NaCl, with ascorbic acid as an initiator to afford the planar derivative 4,6-dihydro-1,4,6,8-tetramethyl-3-phenyldipyrazolo[3,4-b:4′,3′-d]pyridin-5(3H)-one (16) and its unexpected isomer 4,6-dihydro-3,4,6,8-tetramethyl-1-phenyldipyrazolo[4,3-b:4′,3′-d]pyridin-5(1H)-one (17), as well as the epimers (3S,4S)- (or (3S,4R)-) and (3S,4R)- (or (3S,4S)-) 4-chloro-2,4-dihydro-1′,3′,5,5′-tetramethyl-2-phenylspiro[pyrazole-3,4′(1′H)-pyrrolo[3,4-c]pyrazol]-6′(5′H)-one (18a and b, respectively). Epimers 18a and b were converted under basic c…
Eye Cataract Simulation Using Polymer Dispersed Liquid Crystal Scattering Obstacles
2004
Polymer dispersed liquid crystals with electrically induced variations of light scattering extent similar to that of transparent PLZT ceramics are used for simulation of different development stages of eye cataract. Wavelength dependencies of scattering are determined in the visible spectral range, and human visual response looking through the scattering obstacle to the onset of various spatial frequency stimuli is determined psychophysically and electrophysiologically in order to find correlation between the scattering extent, visual acuity and visual evoked potential VEP chromatic characteristics.
Lipid and fatty acid profile of the retina, RPE/choroid and lacrimal gland, and associations with dietary fatty acids in human subjects
2008
Purpose The contribution of dietary lipids to the accumulation of lipids in the retina during ageing and in the course of age related maculopathies remains under debate. Our objective was to establish associations between fatty acid profiles of ocular structures, and adipose tissue as a surrogate for the past dietary intake of the subjects. Methods Lipids and fatty acids were analyzed by tandem thin-layer chromatography-flame ionization detection and gas chromatography-flame ionization detection from the neural retina, RPE/choroid, lacrimal gland and adipose tissue, collected from 19 women and 8 men, aged 59–95 years. Results DHA concentrations in the neural retina were positively associate…
ChemInform Abstract: Baeyer-Villiger Oxidation of Ketones with a Silica-Supported Peracid in Supercritical Carbon Dioxide under Flow Conditions.
2009
[2-Percarboxyethyl]-functionalized silica reacts with ketones in supercritical carbon dioxide at 250 bar and 40 °C under flow conditions to yield the corresponding esters and lactones. The solid reagent can be easily recycled through treatment with 70% hydrogen peroxide in the presence of an acid at 0 °C. This procedure not only simplifies the isolation of the reaction products, but has the advantage of using only water and carbon dioxide as solvents under mild conditions.
Design, synthesis and evaluation of chromo and fluorogenic chemosensors to detect liquid ecstasy
2022
El éxtasis líquido o gamma hidroxibutirato (GHB) es un ácido graso de cadena corta que se encuentra de manera natural en el cuerpo de los seres humanos debido a su producción mediante el metabolismo del GABA (ácido gamma aminobutírico). Hace unas décadas se empleaba en medicina como anestésico debido a su capacidad de actuar como depresor del sistema nervioso central. Conocido como oxibato de sodio, actualmente todavía es utilizado en algunos países para tratar trastornos del sueño, como la narcolepsia, el síndrome de abstinencia de personas alcohólicas o la cataplejía. No obstante, precisamente debido a esas propiedades anestésicas y sedativas, este compuesto es ampliamente en usado en agr…
Relationship of choroidal thickness with pulsatile hemodynamics in essential hypertensive patients
2021
Controversy exists about the association of choroidal thickness (CTh) with blood pressure (BP) values. There is some evidence suggesting that central hemodynamics changes are associated with microvascular disease. Our study was aimed to assess the relationships between CTh and clinic and 24-h BP and between CTh and estimated 24-h aortic pulse pressure (aPP), 24-h aortic systolic BP (aSBP), and 24-h aortic augmentation index (aAIx) in a group of hypertensive patients. We enrolled 158 hypertensive subjects (mean age 48 ± 13 years) all of which underwent evaluation of the choroidal district by Swept-Source optical coherence tomography (SS-OCT) and 24-h BP monitoring, in order to measure periph…
Effect of the color of the intraocular lens on optical and visual quality
2014
Purpose: To analyze the optical quality of intraocular lenses (IOL) with an orange (PC440Y) and a yellow (SN60AT) filter, and correlate these results with the visual quality of patients with these implants. Setting: Fisabio Oftalmología Médica, Valencia, Spain. Design: Randomized prospective study. Materials and Methods: The IOL optical quality was determined using the modulation transfer function (MTF) and the spectral transmission. The visual quality of 87 eyes with cataract (51 with orange filter and 36 with yellow filter) was determined by best corrected visual acuity (BCVA) and contrast sensitivity function (CSF) under photopic and mesopic conditions. To analyze the results, we use a S…
PCARE and WASF3 regulate ciliary F-actin assembly that is required for the initiation of photoreceptor outer segment disk formation
2020
Significance The photoreceptor outer segments are primary cilia, modified for phototransduction by incorporation of stacked opsin-loaded membrane disks that are continuously regenerated. This process is disrupted in several types of inherited retinal dystrophy, but the driving force remained unclear. We show that C2orf71/PCARE (photoreceptor cilium actin regulator), associated with inherited retinal dystrophy subtype RP54, efficiently recruits the Arp2/3 complex activator WASF3 to the cilium. This activates an actin dynamics-driven expansion of the ciliary tip, resembling membrane evagination in lamellipodia formation. Colocalization of this actin dynamics module to the base of the outer se…