Search results for " Structures"
showing 10 items of 4162 documents
Zizyphus lotus L. (Desf.) modulates antioxidant activity and human T-cell proliferation
2009
Abstract Background Zizyphus lotus L. (Desf.) also known as Jujube, is a deciduous shrub which belongs to Rhamnaceae family. This plant is used in Algerian traditional medicine for its anti-diabetic, sedative, analgesic, anti-inflammatory and hypoglycaemic activities. In the present study, we determined the concentrations of different vitamins (vitamin A, C and E) and fatty acids in root, stem, leaves, fruit pulp and seed of Zizyphus lotus L. (Desf.) and assessed the effects of their aqueous extracts on antioxidant status and human T-cell proliferation. Methods Aqueous filtrates from different parts, i.e, root, leaf, stem, fruit pulp and seed, of Zizyphus lotus L. (Desf.) were prepared. Vit…
Prenatal androgen exposure modulates cellular and humoral immune function of black-headed gull chicks
2005
Avian eggs contain considerable amounts of maternal yolk androgens, which have been shown to beneficially influence the physiology and behaviour of the chick. As androgens may suppress immune functions, they may also entail costs for the chick. This is particularly relevant for colonial species, such as the black-headed gull (Larus ridibundus), in which the aggregation of large numbers of birds during the breeding season enhances the risk of infectious diseases for the hatching chick.To test the effect of maternal yolk androgens on the chick's immune function, we experimentally manipulated, in a field study, yolk androgen levels within the physiological range by in ovo injection of either a…
Bleach interference in forensic luminol tests on porous surfaces: more about the drying time effect.
2009
As criminals try to avoid leaving clues at the scene of a crime, bloodstains are often washed away, but fortunately for investigators, they are difficult to eliminate completely. Porous surfaces easily retain blood traces, which are sometimes invisible to the naked eye. The reagent of choice for detecting latent blood traces on all types of surfaces is luminol, but its main disadvantage is a high degree of sensitivity to oxidising contaminants in the blood sample. If household bleach is used to clean bloodstains, presumptive tests are invalidated. Hypochlorites, however, are known to be unstable and deteriorate over time, and this feature could be of help in preventing household bleach-indu…
Evaluation of the effect of different enamel surface treatments and waiting times on the staining prevention after bleaching
2017
Background Bleached dental enamel can be more susceptible to staining than the enamel that has never been bleached, especially right after tooth bleaching. The aim of this study is to evaluate the effect of surface treatments and waiting time prior to contact with dye on bleached enamel staining susceptibility. Material and Methods One hundred teeth were bleached with 35% hydrogen peroxide (Whiteness HP, FGM) and randomly assigned to G1 artificial saliva, G2 2% sodium fluoride (Flugel, Nova DFL), G3 casein phosphopeptide-amorphous calcium phosphate fluoride paste (CPP-ACPF, MI Paste Plus, GC America), G4 rinse for color maintenance after bleaching (Keep White Rinse, DMC) and G5 polishing wi…
New-stage discharge relationship for weirs of finite crest lenght
2014
AbstractThe flow process of weirs of finite crest length is analyzed on the basis of the dimensional analysis and incomplete self-similarity theory. The crest length is incorporated in the functional stage-discharge relationship for weirs of finite crest length. The theoretically deduced stage-discharge formula was then calibrated using the experimental data compiled in this research. According to the current experimental data it is also concluded that the performance of the proposed stage-discharge formula is better than the previous dimensional stage-discharge formulae. Also, the proposed stage-discharge formula is applicable for all types of the weirs, i.e., long-crested, broad-crested, …
Comparison of higher order aberrations measured by NIDEK OPD-Scan dynamic skiascopy and Zeiss WASCA Hartmann-Shack aberrometers.
2008
<h4>PURPOSE</h4><p>To compare the measurement of wavefront aberrations in non-cyclopleged human eyes with Hartmann-Shack and dynamic skiascopy wavefront analyzers.</p> <h4>METHODS</h4><p>Eighty eyes of 40 healthy young adults (19 men, 21 women; mean age 20.8±2.5 years) with refractive errors ranging from +1.50 to –9.75 diopters (D) sphere and up to 1.75 D cylinder (mean spherical equivalent refraction –2.12±2.69 D) were examined with the Zeiss/Meditec WASCA and NIDEK OPD-Scan wavefront analyzers and with the Nippon SRW5000 binocular, open-field autorefractor without the instillation of antimuscarinic agents. Three measurements were taken with each s…
In vitro optical performance of a new aberration-free intraocular lens
2014
To assess the optical performance of the new EnVista intraocular lens (IOL). Four aspheric IOLs were evaluated; the new EnVista is one amoung them. This IOL, similarly to the Z-Flex HB and the Bi-Flex 1.8 667AB ones, has a neutral aspheric design, whereas the fourth IOL under test (AcrySof IQ IOL SN60WF) presents a negative spherical aberration (SA). The IOL’s aberration patterns were measured in vitro, by setting them up on an optical bench. From these aberration-pattern data, the modulation transfer function (MTF), the average modulation values, and the points spread function (PSF) were calculated. Furthermore, in order to assess the potential optical quality that these IOLs would yield o…
Ultrathin high-index metasurfaces for shaping focused beams
2015
The volume size of a converging wave, which plays a relevant role in image resolution, is governed by the wavelength of the radiation and the numerical aperture (NA) of the wavefront. We designed an ultrathin (λ/8 width) curved metasurface that is able to transform a focused field into a high-NA optical architecture, thus boosting the transverse and (mainly) on-axis resolution. The elements of the metasurface are metal-insulator subwavelength gratings exhibiting extreme anisotropy with ultrahigh index of refraction for TM polarization. Our results can be applied to nanolithography and optical microscopy. Spanish Ministry of Economy and Competitiveness (MEC) (TEC2013-50416-EXP).
<title>Photoinduced AsSeS thin film phase plates as adaptive optics mirrors for eye aberration correction</title>
2008
Amorphous chalcogenide thin films are excellent materials for holographic recordings. AsSeS thin film coating is a useful optical material for it's thickness to be easily corrected with the use of exposure to light and consecutive chemical etching. Following properties allow to treat the surface of AsSeS chalcogenide films and to use them in adaptive optics systems for correction of the optical wavefront. Hereby, we characterize AsSeS film properties to be used for correction of optical aberrations of the human eye. The thickness of the film is characterized with the method of spectrodensitometry and the surface profile depth with a Hartman- Shack waveform analyzator.
Neural Adaptation to Optical Quality Defects
2010
From an optical perspective the eye is far from perfect. This is a fact that is extensively supported by literature; for instance, Prof. Navarro recently provided us with a fantastic critical review on the various theories behind the different eye models and their flaws.1 The human eye has considerable amounts of higher-order aberrations even when it is emmetropic,2 with great inter-individual variability. Besides, higher-order aberrations are still postulated to have a role in the development of the refractive error, although it is not clear the extent to which this may be (see Charman WN for a review).3 The known optical limitations of the normal human eye raised the question as to what t…