Search results for "thickness"
showing 10 items of 307 documents
Variations in central corneal thickness during the menstrual cycle in women.
2007
PURPOSE: We report changes in the central corneal thickness during various phases of the menstrual cycle. METHODS: We recruited 16 healthy women of reproductive age and measured the central corneal thickness at 3 points in their menstrual cycle, beginning on days 1 to 3 and again at ovulation and at the end of the cycle (days 27-32). Ovulation was determined with a test that determines the peak of luteinizing hormone in the urine. RESULTS: We found that the central cornea was thinnest at the beginning of the cycle (mean = 536 microm). Corneal thickness increased at ovulation (mean = 549 microm) and at the end of the cycle (mean = 559 microm). The difference in corneal thickness was statisti…
Chromatic and achromatic visual fields in relation to choroidal thickness in patients with high myopia: A pilot study
2018
Purpose. - To analyse the relationship between the choroidal thickness and the visual perception of patients with high myopia but without retinal damage. Methods. - All patients underwent ophthalmic evaluation including a slit lamp examination and dilated ophthalmoscopy, subjective refraction, best corrected visual acuity, axial length, optical coherence tomography, contrast sensitivity function and sensitivity of the visual pathways. Results. - We included eleven eyes of subjects with high myopia. There are statistical correlations between choroidal thickness and almost all the contrast sensitivity values. The sensitivity of magnocellular and koniocellular pathways is the most affected, an…
Meta-analysis of genome-wide association studies from the CHARGE consortium identifies common variants associated with carotid intima media thickness…
2011
Carotid intima media thickness (cIMT) and plaque determined by ultrasonography are established measures of subclinical atherosclerosis that each predicts future cardiovascular disease events. We conducted a meta-analysis of genome-wide association data in 31,211 participants of European ancestry from nine large studies in the setting of the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) Consortium. We then sought additional evidence to support our findings among 11,273 individuals using data from seven additional studies. In the combined meta-analysis, we identified three genomic regions associated with common carotid intima media thickness and two different regions a…
Effects of PCSK9 variants on common carotid artery intima media thickness and relation to ApoE alleles.
2009
BACKGROUND: PCSK9 plays a key role in plasma cholesterol metabolism by modulating the expression of LDL receptors. OBJECTIVE AND METHODS: In this study we investigated the effects of two common polymorphism of the PCSK9 gene (E670G and I474V) on the intima media thickness of the common carotid artery and the possible relation with polymorphisms of apolipoprotein E in 1541 middle aged subjects selected from the general population enrolled in the PLIC study and confirmed the major findings in a second free-living population enrolled in the Ventimiglia study. RESULTS: 670G carriers showed significantly increased plasma total cholesterol, LDL-cholesterol, and Apo levels B while no significant d…
Existence and Singularities for the Prandtl Boundary Layer Equations
2000
Prandtl's boundary layer equations, first formulated in 1904, resolve the differences between the viscous and inviscid description of fluid flows. This paper presents a review of mathematical results, both analytic and computational, on the unsteady boundary layer equations. This includes a review of the derivation and basic properties of the equations, singularity formation, well-posedness results, and infinite Reynolds number limits.
Inferences of dietary preferences of Miocene squirrels (Xerinae, Sciuridae) from the Iberian Peninsula and Namibia using microwear analyses and ename…
2020
In this work, we compared microwear features and enamel thickness from upper molars (M1 and M2) of extinct Xerinae squirrels from the Miocene of Namibia (Vulcanisciurus sp) and the Iberian Peninsula (Atlantoxerus nov. sp. and Heteroxerus rubricati). We also examined the microwear from young and adult specimens of one extant squirrel, Atlantoxerus getulus, to compare it with the extinct species. Both, the microwear features and enamel thickness showed that the Miocene African species presented a more abrasive diet than the Iberian ones.
Comparing airborne and satellite retrievals of cloud optical thickness and particle effective radius using a spectral radiance ratio technique: two c…
2018
Solar radiation reflected by cirrus and deep convective clouds (DCCs) was measured by the Spectral Modular Airborne Radiation Measurement System (SMART) installed on the German High Altitude and Long Range Research Aircraft (HALO) during the Mid-Latitude Cirrus (ML-CIRRUS) and the Aerosol, Cloud, Precipitation, and Radiation Interaction and Dynamic of Convective Clouds System – Cloud Processes of the Main Precipitation Systems in Brazil: A Contribution to Cloud Resolving Modelling and to the Global Precipitation Measurement (ACRIDICON-CHUVA) campaigns. On particular flights, HALO performed measurements closely collocated with overpasses of the Moderate Resolution Imaging Spectroradiometer (…
Influence of Saharan dust on cloud glaciation in southern Morocco during the Saharan Mineral Dust Experiment
2008
[1] Multiwavelength lidar, Sun photometer, and radiosonde observations were conducted at Ouarzazate (30.9°N, 6.9°W, 1133 m above sea level, asl), Morocco, in the framework of the Saharan Mineral Dust Experiment (SAMUM) in May–June 2006. The field site is close to the Saharan desert. Information on the depolarization ratio, backscatter and extinction coefficients, and lidar ratio of the dust particles, estimates of the available concentration of atmospheric ice nuclei at cloud level, profiles of temperature, humidity, and the horizontal wind vector as well as backward trajectory analysis are used to study cases of cloud formation in the dust with focus on heterogeneous ice formation. Surpris…
Ocular biometry with swept-source optical coherence tomography
2020
This study aimed to summarize the outcomes reported when swept-source optical coherence tomography (SS-OCT) is used for ocular biometry. A literature search was performed to identify publications reporting clinical outcomes of patients measured with commercial SS-OCT. Twenty-nine studies were included in this review. A comprehensive analysis of the available data was performed, focusing on parameters used for intraocular lens (IOL) power calculation in cataract surgery, including keratometry, central corneal thickness, white-to-white distance, anterior chamber depth, lens thickness, axial length, IOL power, and pupil diameter. Different metrics for repeatability, reproducibility, and agreem…
Association Between Carotid Atherosclerosis and Metabolic Syndrome: Results From the ISMIR Study
2010
The metabolic syndrome (MetS) has previously been associated with an early marker of atherosclerosis, the carotid intima-media thickness (IMT). From the ISMIR (Ispessimento Medio Intimale e Rischio cardiovascolare [media-intima thickness and cardiovascular risk]) study population of 479 asymptomatic participants, we identified 80 participants with MetS. Carotid IMT and plaques were evaluated by ultrasonography. Blood samples were obtained from all participants. Participants with MetS had a significantly higher prevalence of a carotid IMT > 0.80 mm (P = .004) and of carotid plaques (P < .001) as compared with participants without MetS. Carotid IMT was significantly correlated with fas…