scholarly journals Corneal Vibrations during Intraocular Pressure Measurement with an Air-Puff Method

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Robert Koprowski ◽  
Sławomir Wilczyński
Keyword(s):  
Intraocular Pressure ◽  
Measurement Method ◽  
Image Sequences ◽  
The Other ◽  
Pressure Measurements ◽  
Automatic Determination ◽  
Diagnostic Features ◽  
Characteristic Points ◽  
Eye Pressure

Introduction. The paper presents a commentary on the method of analysis of corneal vibrations occurring during eye pressure measurements with air-puff tonometers, for example, Corvis. The presented definition and measurement method allow for the analysis of image sequences of eye responses—cornea deformation. In particular, the outer corneal contour and sclera fragments are analysed, and 3D reconstruction is performed. Methods. On this basis, well-known parameters such as eyeball reaction or corneal response are determined. The next steps of analysis allow for automatic and reproducible separation of four different corneal vibrations. These vibrations are associated with (1) the location of the maximum of cornea deformation; (2) the cutoff area measured in relation to the cornea in a steady state; (3) the maximum of peaks occurring between applanations; and (4) the other characteristic points of the corneal contour. Results. The results obtained enable (1) automatic determination of the amplitude of vibrations; (2) determination of the frequency of vibrations; and (3) determination of the correlation between the selected types of vibrations. Conclusions. These are diagnostic features that can be directly applied clinically for new and archived data.

scholarly journals Automatic determination of the dual system width of to a bivalent system

2018 ◽  
Vol XIX (1) ◽  
pp. 58-64
Author(s):  
Vasiliu Paul
Keyword(s):  
Dual System ◽  
The Other ◽  
Automatic Determination ◽  
Stable States ◽  
System A ◽  
Minimum Number

A system is a set of elements that can be found in one of the following states: operating state and fault. Any system has two stable states: functioning and defect, which is why, in the theory of reliability, it is called a bivalent system. A subset of defective elements is called the system cut if all the other elements of the system are in operation and the system is defective. The width of a bivalent system is equal to the minimum number of elements the system cuts have. In this paper is presented an algorithm for automatic determination of the dual system width to a bivalent system, a Matlab script that implements the algorithm, a case study and subsequent directions of development.

scholarly journals Algorithm for Automatic Determination of the Width of a Bivalent System

2018 ◽  
Vol 24 (3) ◽  
pp. 89-94
Author(s):  
Paul Vasiliu
Keyword(s):  
Subsequent Development ◽  
The Other ◽  
Automatic Determination ◽  
Stable States ◽  
System A ◽  
Minimum Number

Abstract A system is a set of elements that can be found in one of the following states: operating state and fault. Any system has two stable states: functioning and defect, which is why, in the theory of reliability, it is called a bivalent system. A subset of defective elements is called the system cut if all the other elements of the system are in operation and the system is defective. The width of a bivalent system is equal to the minimum number of elements the system cuts have. In this paper we present an algorithm for automatic determination of the width of a bivalent system, a Matlab script that implements the algorithm, a case study and subsequent development directions

CHANGE IN EYE HYDRODYNAMICS AS A PATHOGENESIS FACTOR OF THE SPACE-FLIGHT ASSOCIATED NEURO-OCULAR SYNDROME (SANS)

2021 ◽  
Vol 55 (1) ◽  
pp. 38-45
Author(s):  
О.М. Man'ko ◽  
◽  
А.Е. Smoleevsky ◽  
Е.S. Tomilovskaya ◽  
◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Fluid Balance ◽  
Space Flight ◽  
Pressure Measurements ◽  
Visual Analyzer ◽  
Space Medicine ◽  
Clinically Significant ◽  
Balance Dynamics ◽  
Male Subjects

Studies of the mechanisms of visual analyzer adaptation in remote space missions are of paramount importance in the domain of space medicine. Pathogenesis of ocular nerve edema, the fundamental symptom of space-flight associated neuro-ocular syndrome (SANS), remains unclear. One of the hypothesized SANS trigger is a change of the pressure gradient in the sclera lattice coat of the membrane due to fluctuations of both the intracranial and intraocular pressures in the absence of gravity. This work extended the previous studies of ocular hydrodynamics during 5-day simulation of the microgravity body effects by dry immersion. We present the results of intraocular hydrobalance analysis after 21-d DI with participation of 8 male subjects at the age of 24 to 35 years. Data of electron tonography and diurnal intraocular pressure measurements were correlated with the fluid balance dynamics. Ocular hydrodynamics disbalance was registered in 80 % of the subjects. Tonography revealed clinically significant changes in 25 % of the subjects. These results enabled determination of the degree and character of ocular hydrodynamics autoregulation in the condition of compensatory body hypohydration.

Determination of the lattice translation across {110} APBs in GaAs

1988 ◽  
Vol 46 ◽  
pp. 600-601
Author(s):  
D.R. Rasmussen ◽  
N.-H. Cho ◽  
C.B. Carter
Keyword(s):  
Grain Boundaries ◽  
Lower Energy ◽  
Antiphase Boundary ◽  
The Other ◽  
Boundary Structure ◽  
Interface Plane ◽  
Inversion Symmetry ◽  
High Angle ◽  
Equilibrium Distance

Domains in GaAs can exist which are related to one another by the inversion symmetry, i.e., the sites of gallium and arsenic in one domain are interchanged in the other domain. The boundary between these two different domains is known as an antiphase boundary [1], In the terminology used to describe grain boundaries, the grains on either side of this boundary can be regarded as being Σ=1-related. For the {110} interface plane, in particular, there are equal numbers of GaGa and As-As anti-site bonds across the interface. The equilibrium distance between two atoms of the same kind crossing the boundary is expected to be different from the length of normal GaAs bonds in the bulk. Therefore, the relative position of each grain on either side of an APB may be translated such that the boundary can have a lower energy situation. This translation does not affect the perfect Σ=1 coincidence site relationship. Such a lattice translation is expected for all high-angle grain boundaries as a way of relaxation of the boundary structure.

Determination of the Burgers vector of a dislocation in a Fe-Mn alloy by weak-beam image in HVEM

1978 ◽  
Vol 36 (1) ◽  
pp. 330-331
Author(s):  
Y. Ishida ◽  
H. Ishida ◽  
K. Kohra ◽  
H. Ichinose
Keyword(s):  
High Order ◽  
Simulation Technique ◽  
The Other ◽  
Image Simulation ◽  
Diffraction Vector ◽  
Burgers Vector ◽  
Weak Beam ◽  
Beam Image ◽  
Edge Component

IntroductionA simple and accurate technique to determine the Burgers vector of a dislocation has become feasible with the advent of HVEM. The conventional image vanishing technique(1) using Bragg conditions with the diffraction vector perpendicular to the Burgers vector suffers from various drawbacks; The dislocation image appears even when the g.b = 0 criterion is satisfied, if the edge component of the dislocation is large. On the other hand, the image disappears for certain high order diffractions even when g.b ≠ 0. Furthermore, the determination of the magnitude of the Burgers vector is not easy with the criterion. Recent image simulation technique is free from the ambiguities but require too many parameters for the computation. The weak-beam “fringe counting” technique investigated in the present study is immune from the problems. Even the magnitude of the Burgers vector is determined from the number of the terminating thickness fringes at the exit of the dislocation in wedge shaped foil surfaces.

Procedures for the Quantitative Determination of Autoprothrombin C

1962 ◽  
Vol 08 (03) ◽  
pp. 434-441 ◽  
Author(s):  
Edmond R Cole ◽  
Ewa Marciniak ◽  
Walter H Seegers
Keyword(s):  
Quantitative Determination ◽  
Plasma Sample ◽  
Quantitative Measure ◽  
The Other ◽  
Clotting Time ◽  
Bovine Plasma ◽  
Autoprothrombin C

SummaryTwo quantitative procedures for autoprothrombin C are described. In one of these purified prothrombin is used as a substrate, and the activity of autoprothrombin C can be measured even if thrombin is in the preparation. In this procedure a reaction mixture is used wherein the thrombin titer which develops in 20 minutes is proportional to the autoprothrombin C in the reaction mixture. A unit is defined as the amount which will generate 70 units of thrombin in the standardized reaction mixture. In the other method thrombin interferes with the result, because a standard bovine plasma sample is recalcified and the clotting time is noted. Autoprothrombin C shortens the clotting time, and the extent of this is a quantitative measure of autoprothrombin C activity.

Determination of Factor XIII Activity and of Factor XIII Inhibitors Using an Ammonium-Sensitive Electrode

1983 ◽  
Vol 50 (02) ◽  
pp. 563-566 ◽  
Author(s):  
P Hellstern ◽  
K Schilz ◽  
G von Blohn ◽  
E Wenzel
Keyword(s):  
Factor Xiii ◽  
Normal Subjects ◽  
The Other ◽  
Activity Measurement ◽  
Factor Xiii Deficiency ◽  
Assay Procedure ◽  
Stabilization Factor ◽  
Release Method ◽  
Sensitive Electrode

SummaryAn assay for rapid factor XIII activity measurement has been developed based on the determination of the ammonium released during fibrin stabilization. Factor XIII was activated by thrombin and calcium. Ammonium was measured by an ammonium-sensitive electrode. It was demonstrated that the assay procedure yields accurate and precise results and that factor XIII-catalyzed fibrin stabilization can be measured kinetically. The amount of ammonium released during the first 90 min of fibrin stabilization was found to be 7.8 ± 0.5 moles per mole fibrinogen, which is in agreement with the findings of other authors. In 15 normal subjects and in 15 patients suffering from diseases with suspected factor XIII deficiency there was a satisfactory correlation between the results obtained by the “ammonium-release-method”, Bohn’s method, and the immunological assay (r1 = 0.65; r2= 0.70; p<0.01). In 3 of 5 patients with paraproteinemias the values of factor XIII activity determined by the ammonium-release method were markedly lower than those estimated by the other methods. It could be shown that inhibitor mechanisms were responsible for these discrepancies.

On Automatic Determination of Movement Phases in Manual Transport During the Precision Grip

2000 ◽  
Vol 28 (1-2) ◽  
pp. 237-245 ◽  
Author(s):  
Nasser Hosseini ◽  
Blanka Hejdukova ◽  
Pall E. Ingvarsson ◽  
Bo Johnels ◽  
Torsten Olsson
Keyword(s):  
Precision Grip ◽  
Automatic Determination
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