Search results for "corn"

MORPHOMETRIC ANALYSIS OF HUMAN CORNEAL ENDOTHELIUM BY MEANS OF SPATIAL POINT PATTERNS

2002

This paper presents a method for detecting abnormalities in spatial arrangements of cells within any tissue that can be described by different sets of relevant points. The method has been applied to the detection of subtle abnormalities in corneal endothelia. Images of this type of tissue can be characterized by two types of points: cell centroids and triple points associated with the apical intersections as it was proposed by Díaz.7 Both types of points jointly considered are modeled using a bivariate spatial point process; then a statistical analysis based on certain distributional descriptors proposed by Doguwa4,9 is carried out to discriminate severe and subtle abnormalities from contr…

A granulometric analysis of specular microscopy images of human corneal endothelia

2005

The inner layer of the human cornea, called the corneal endothelium, plays an important role in the maintenance of corneal transparency. Specular microscopy is the most widely used technique to study the corneal endothelium in vivo. Improvements in technology have allowed us to obtain good quality specular images, but the detection and quantification of small size-shape cell changes is not obvious, specially when the physician wants to evaluate endothelial cell changes after some surgical procedures. This paper proposes a methodology to analyze specular microscopy images. Every corneal endothelium is described by means of different cumulative distribution functions or some moments (mean, st…

Measuring the Spatial Homogeneity in Corneal Endotheliums by Means of a Randomization Test

1999

Quantification of regularity of cell sizes and the spatial arrangement of cells in corneal endotheliums becomes of a great importance associated to stress situations such as cataract surgery, corneal transplantation or implantation of intra-ocular lenses. A new index of regularity of the spatial distribution of cell sizes in corneal endotheliums is proposed. The corneal endothelium is described by means of a spatial marked point pattern (the cell centroids marked with the cell areas). The hypothesis of no dependency between mark and locations is tested by a Monte Carlo test. The new index is the p-value of the test validating the hypothesis. Pairs of endotheliums from different eyes of the …

Classifying human endothelial cells based on individual granulometric size distributions

2002

Abstract This paper presents an application to a medical problem of methods of shape analysis based on mathematical morphology. The medical problem consists on the detection of abnormalities in the corneal endothelium, a tissue composed by quasi-planar cells of ideally regular hexagonal shape. Images of this tissue are taken by a specular microscope and used to evaluate the corneal endothelium status. Up to now, cell density, hexagonality and an analysis of cell areas are the usual descriptors of a corneal endothelium. These parameters are not sensitive enough to detect subtle lesions. What this paper proposes is an analysis based on granulometries, which are size-shape descriptors widely u…

Set Descriptors for Visual Evaluation of Human Corneal Endothelia

2001

Images of corneal endothelium obtained from specular microscopy are of great importance in the evaluation of the corneal endothelium status. Several commercial tools provide some numerical descriptors to characterize these images in terms of cell density, hexagonality, and some descriptive statistics of the cell areas. However, it is a too simple analysis that only detects severe abnormal endothelia with many irregular and large cells. Detection of subtle abnormalities needs a more refined analysis. This paper proposes a shape-size descriptor based on some modified versions of the geometric covariogram. This descriptor is presented as a valid alternative to the classical analysis that provi…

Corneal thickness and intraocular pressure in pediatric patients with Celiac disease or Inflammatory Bowel Disease

Effects of confinement level, cross-section shape and corner radius on the cyclic behavior of CFRCM confined concrete columns

2014

Abstract The main results of an experimental research aiming to investigate the behavior of medium-size low-strength concrete columns wrapped with Carbon Fiber Reinforced Cementitious Matrix (CFRCM) under monotonic and cyclic compressive axial loads are presented. Thirty columns with circular, square and rectangular cross-sections were tested under monotonic and cyclic axial loads to investigate the effect of the confinement level, the cross-section shape and the corner radius on the stiffness, strength, and ductility of CFRCM confined concrete columns under cyclic loads. The results prove that CFRCM confining jackets provide substantial gain in compressive strength, deformability and absor…

Temple and the merchants

2019

Con i suoi tre milioni di abitanti e un hinterland di quattro milioni, Casablanca potrebbe sembrare a prima vista una metropoli cosmopolita e internazionale. Vivendola dal di dentro, invece, Casa (come familiarmente viene chiamata dagli abitanti) si rivela una città profondamente legata alle sue origini berbere in un paradosso di urbanistica nomade. Abitata da “uomini liberi” (dal significato etimologico del termine “berbero”), la popolazione continua a mantenere usi e costumi propri delle tradizioni nomadi nordafricane. Nella Medina più antica, cinta dalle poderose mura in terra cruda rossa, i bianchi edifici che valsero il nome alla città formano un dedalo di strade e di vicoli ciechi bru…

Exploring the apparent properties and Q-markers for quality control of Cornus officinalis

2023

Cornus officinalis Siebold & Zucc. has a high nutritious value and is widely used in food fields. To distinguish the quality of cornus in different areas, this research provided a new strategy for comprehensively evaluating cornus. As a result, 12 iridoid glycosides and 7 polyphenols were identified and quantified by UHPLC-Q-TOF/MS in 13 batches of samples from five different origins. Chromaticity analysis pointed out that pelargonidin-3-O-galactoside, total iridoids, and total polyphenols performed high relation with 1365*. Antioxidant activity and inhibition of α-glucosidase effect correlated with the chemical analysis suggested that iridoid glycosides and polyphenols should represent…

Evaluation of intraocular pressure and other biomechanical parameters to distinguish between subclinical keratoconus and healthy corneas

2021

(1) Purpose: To assess the main corneal response differences between normal and subclinical keratoconus (SCKC) with a Corvis® ST device. (2) Material and Methods: We selected 183 eyes of normal patients, of a mean age of 33 ± 9 years and 16 eyes of patients with SCKC of a similar mean age. We measured best corrected visual acuity (BCVA) and corneal topography with a Pentacam HD device to select the SCKC group. Biomechanical measurements were performed using the Corvis® ST device. We carried out a non-parametric analysis of the data with SPSS software (Wilcoxon signed rank-test). (3) Results: We found statistically significant differences between the control and SCKC groups in some corneal b…