Search results for "microscopic"

Electron microscopic study on the larval and adult corpus allatum of Oncopeltus fasciatus dallas (insecta, heteroptera)

1973

1. The ultrastructure of the corpora allata of last larval instars and adults of Oncopeltus was studied. The unpaired gland undergoes submicroscopic alterations and shows signs of degradation in old animals. The organ is partly covered and penetrated by corpus cardiacum tissue. Axons with different types of neurosecretory granules form synaptoid contacts with the corpus allatum cells.

[Oral capillaroscopy: a new diagnostic method].

2011

The morphological-functional study of microcirculation is of fundamental importance; in fact, the microvascular bed is directly involved both in autoimmune etiopathogenesis pathologies, and in acute and chronic inflammatory etiopathogenesis pathologies. Oral capillaroscopy is a very stimulating method for studying microcirculation, because of the possibility of studying small vessels in vivo by means of a microscope. Today, it is becoming more reliable thanks to the improvement of the observation tools (photography, videomicroscopy).

Nail fold capillary diameter changes in acute systemic hypoxia.

2013

The present study was undertaken to determine the effect of arterial blood hypoxemia induced by acute systemic hypoxia (pO2=12%) on capillary recruitment and diameter, and red blood cell (RBC) velocity in human nail fold capillaries during rest, arterial post-occlusive reactive hyperemia (PRH), and venous occlusion (VO) using intravital video-capillaroscopy. Capillary recruitment was unchanged in acute systemic hypoxia (H) versus normoxia (N). There was no difference in RBC velocity measurements between normoxia and hypoxia (P<0.63). However, a statistically significant increase in nail fold capillary total width (N, 39.9±9.1 vs. H, 42.7±10.3 μm; P<0.05), apical diameter (N, 15.5±4.3 vs. H,…

Assessment and grading of mucosal inflammation in colonic diverticular disease.

2008

Goal: The aim of this study was to assess and grade the mucosal inflammatory infiltrate in different degrees of diverticular disease (DID) and to compare them with healthy matched controls. Background: Mucosal inflammation in colonic DD has never been investigated. In particular, it is unknown whether inflammation may be found in every degree of DD. Materials and Methods: Thirty consecutive patients with a new endoscopic diagnosis of D-D (10 with asymptomatic diverticulosis, 10 with symptomatic uncomplicated DD, and 10 with acute uncomplicated diverticulitis) and 10 healthy controls were studied. Results: A neutrophilic inflammatory infiltrate was found only in acute uncomplicated diverticu…

Permanence of Modifications in Oral Microcirculation in Ex-Smokers.

2019

Background: The aim of this study was to assess the long-term effects of smoking and to investigate the permanence of this damage to the oral microcirculation. Material/Methods: We recruited 75 patients and divided them into 3 groups: group 1 was composed of 25 healthy non-smokers, group 2 was composed of 25 healthy current smokers, and group 3 was composed of 25 healthy ex-smokers. Video-capillaroscopic examination was performed on all patients. The video-capillaroscopic investigation was performed on patients in sitting position, always with the same light source, at the same room temperature (23°C), in the morning, with the same operator (GAS), and was repeated many times for every area …

Electron microscopic investigations on amorphous polycarbonate

1967

Glass transition in confined geometry.

2010

Extending mode-coupling theory, we elaborate a microscopic theory for the glass transition of liquids confined between two parallel flat hard walls. The theory contains the standard MCT equations in bulk and in two dimensions as limiting cases and requires as input solely the equilibrium density profile and the structure factors of the fluid in confinement. We evaluate the phase diagram as a function of the distance of the plates for the case of a hard sphere fluid and obtain an oscillatory behavior of the glass transtion line as a result of the structural changes related to layering.

A quantitative electron microscopic study of the crystalline structure of ethylene copolymers

1986

Etude de sections minces sur des fractions de composition de copolymeres cristallises dans des conditions extremement severes

MICRO-SCALE STUDY OF RESIDUAL STRESSES IN CR2O3 COATINGS SPRAYED BY APS

2020

International audience; Whichever the application field, every material forming process generates residual stresses on the surface. While they are likely to enhance the aimed properties of the final mechanical part, these stresses may also drastically reduce them and result in early failures. Therefore, understanding the residual stress state remains a major challenge when coating complex parts, especially as most characterization methods at the microscopic scale involve specific sample preparation procedures which may affect the residual stresses field. This work investigates the residual stress state that exists in chromium oxide coatings deposited via Atmospheric Plasma Spray (APS), usin…

Mechanical and Thermal Stability of Adhesive Membranes with Nonzero Bending Rigidity

2010

Membranes at a microscopic scale are affected by thermal fluctuations and self-adhesion due to van der Waals forces. Methods to prepare membranes of even molecular scale, e.g., graphene, have recently been developed, and the question of their mechanical and thermal stability is of crucial importance. To this end we modeled microscopic membranes with an attractive interaction and applied Langevin dynamics. Their behavior was also analyzed under external loading. Even though these membranes folded during isotropic compression as a result of energy minimization, the process at high confinement was similar to crumpling of macroscopic nonadhesive sheets. The main difference appeared when the com…