Search results for "Light"
showing 10 items of 3575 documents
Spectral Transmission of the Human Crystalline Lens in Adult and Elderly Persons: Color and Total Transmission of Visible Light
2012
Purpose To experimentally measure the spectral transmission of human crystalline lenses belonging to adult and elderly persons, and to determine the color and total transmission of visible light of such crystalline lenses. Methods The spectral transmission curve of 32 human crystalline lenses was measured using a PerkinElmer 800UV/VIS spectrometer. Total transmission of visible light and the chromatic coordinates of these crystalline lenses were determined from these curves for solar illumination. Results The crystalline lens that filters UV and its transmission in the visible spectrum decreases with age; such a decrease is greater for short wavelengths. The total transmission of visible li…
Reproducibility of optical biometry using partial coherence interferometry: intraobserver and interobserver reliability
2001
Abstract Purpose: To evaluate the intraobserver and interobserver variability in axial length (AL), anterior chamber depth (ACD), and corneal radius measurements using an optical biometry instrument based on partial coherence interferometry (PCI). Setting: Johannes Gutenberg University, Mainz, Germany. Methods: In this observational case series and interobserver reliability trial, 30 healthy, emmetropic to moderately myopic eyes of 15 volunteers were evaluated. The AL, ACD, and corneal radius were measured 20 times in 10 eyes by 1 observer to evaluate the intraobserver variability. To evaluate the interobserver variability, the measurements were taken in 20 eyes by 5 different observers. Me…
In Lysinuric Protein Intolerance system y+L activity is defective in monocytes and in GM-CSF-differentiated macrophages
2010
Abstract Background In the recessive aminoaciduria Lysinuric Protein Intolerance (LPI), mutations of SLC7A7/y+LAT1 impair system y+L transport activity for cationic amino acids. A severe complication of LPI is a form of Pulmonary Alveolar Proteinosis (PAP), in which alveolar spaces are filled with lipoproteinaceous material because of the impaired surfactant clearance by resident macrophages. The pathogenesis of LPI-associated PAP remains still obscure. The present study investigates for the first time the expression and function of y+LAT1 in monocytes and macrophages isolated from a patient affected by LPI-associated PAP. A comparison with mesenchymal cells from the same subject has been a…
The effects of post-awakening light exposure on the cortisol awakening response in healthy male individuals.
2019
Abstract Background It is assumed that the expression of the cortisol awakening response (CAR) is modulated by light exposure during the peri-awakening period. While initial evidence supports this principal effect, the specific role of the spectral composition of light (brightness and wavelength) is still incompletely understood. Method Two counterbalanced within-subject experiments were conducted in a standardized sleep laboratory setting to investigate the effect of light intensity (study I; two days: dim vs. bright light) and spectral composition (study II; three days: red vs. blue vs. green light) on the CAR. Across studies, light exposure was conducted for one-hour post-awakening and t…
Colour Constancy in Goldfish and Man: Influence of Surround Size and Lightness
2002
Colour constancy was investigated by using a series of 10 simultaneously presented surface colours ranging in small steps from green through gray to red – purple. Goldfish were trained to select one medium test field when the entire setup was illuminated with white light. In the tests, either red or green illumination was used. Colour constancy, as inferred from the choice behaviour, was perfect under green illumination when the test fields were presented on a gray or a white background, but imperfect on a black background. Under red illumination and a white background, however, colour constancy was overcompensated. Here, a colour contrast effect was observed. The influence of background l…
Clinical efficacy of semiconductor laser application as an adjunct to conventional scaling and root planing.
2005
Background and Objectives: The aim of the in vitro study was to examine the clinical efficacy of semiconductor laser periodontal pocket irradiation as an adjunct to conventional scaling and root planing. Materials and Methods: Twenty-two healthy patients with a need of periodontal treatment (15 women, 7 men, mean age 45.0� 10.8 years) with at least four teeth in all quadrants, were included. All of them underwent a conventional periodontal treatment including scaling and root planing. Using a split mouth design, two randomly chosen quadrants (one upper and the corresponding lower one) were subsequently treated with an 809 nm GaAlAs laser operated at a power output of 1.0 Watt using a 0.6 mm…
Sensorimotor adaptation of point-to-point arm movements after spaceflight: the role of internal representation of gravity force in trajectory plannin…
2011
International audience; After an exposure to weightlessness, the central nervous system operates under new dynamic and sensory contexts. To find optimal solutions for rapid adaptation, cosmonauts have to decide whether parameters from the world or their body have changed and to estimate their properties. Here, we investigated sensorimotor adaptation after a spaceflight of 10 days. Five cosmonauts performed forward point-to-point arm movements in the sagittal plane 40 days before and 24 and 72 h after the spaceflight. We found that, whereas the shape of hand velocity profiles remained unaffected after the spaceflight, hand path curvature significantly increased 1 day after landing and return…
Influence of stimulus color on the control of reaching-grasping movements.
2001
This kinematic study aimed to determine whether color is a stimulus property involved in the control of reaching-grasping movements. Subjects reached and grasped a target-object, located either on the right or on the left of the subject's midline. A distractor, placed along the subject's midline, could be randomly presented. The colors, i.e., both chromaticity (red and green stimuli were presented) and lightness, of the target and distractor were varied in experiment 1. Only stimulus lightness and only stimulus chromaticity were varied in experiments 2 and 3, respectively. In experiment 4 subjects matched with their thumb and index finger the size of the target-stimuli presented in experime…
The effects of light exposure on the cortisol stress response in human males.
2020
It is assumed that the production of cortisol is modulated by light exposure. While initial evidence supports this principal effect, the specific effect of light (intensity and wavelength) onto the cortisol stress response is still not completely understood. One between-subject experiment was conducted in a standardized sleep laboratory setting to investigate the effect of light intensity (dim white vs. bright white light) and spectral composition (red vs. blue) on the cortisol response after the Maastricht Acute Stress Test (MAST). 112 healthy young males (24.83 ± 4.10 years of age) were randomly assigned to one of the four light conditions. Across conditions, light exposure was conducted …
Comparison of Cortisol Stress Response in Patients with Panic Disorder, Cannabis-Induced Panic Disorder, and Healthy Controls
2018
<b><i>Background/Aims:</i></b> Little research effort has so far been dedicated to the analysis of the hypothalamic-pituitary-adrenal axis of aetiologically differing subgroups of patients with panic disorder (PD). The current study aimed at a deeper understanding of the cortisol stress response in cannabis-induced PD (CIPD) patients. <b><i>Methods:</i></b> Matched groups of 7 PD patients (mean age ± SD: 32.95 ± 9.04 years), 7 CIPD patients (31.94 ± 8.40 years), and 7 healthy controls (HC) (31.13 ± 8.57 years) were included in the study. The Trier Social Stress Test (TSST) was used for stress induction. Salivary cortisol samples were collected…