PURPOSE The purpose of the present study was to develop mathematical relationships that allow obtaining equilibrium water content and refractive index of conventional and silicone hydrogel soft contact lenses from refractive index measures obtained with automated refractometry or equilibrium water content measures derived from manual refractometry, respectively. METHODS Twelve HEMA-based hydr...

Medicinal and flavoring herbs are widely used in herbal medicine. Various methods to study plants, evaluate the efficiency of extraction biologically active target components. The process control is carried out by chromatographic, spectral methods. search for new fast, affordable, simple analysis currently relevant. dry droplet weighing method extract was proposed as an alternative known herb p...

Zero-order ray paths are examined in radially inhomogeneous spheres with differentiable refractive index profiles. It is demonstrated that zero-order and sometimes twin zero-order bows can exist when the gradient of refractive index is sufficiently negative. Abel inversion is used to "recover" the refractive index profiles; it is therefore possible in principle to specify the nature and type of...

A simplified method for the analysis of both the glyceride-rich Sf 20-1 O5 and the cholesterol-rich St 0-20 lowdensity lipoproteins is presented. It consists of serum lipoprotein fractionation by preparative ultracentrifugation and subsequent quantitative analysis by refractometry. Comparison of this technique with the technically more difficult analytic ultracentrifugal methodology reveals com...

Refractometry of air is a central problem for interferometer-based dimensional measurements. Refractometry at the 10−9 level is only valid if air temperature gradients are controlled at the millikelvin (mK) level. Very precise tests of second-generation National Institute of Standards and Technology (NIST) refractometers involve comparing two instruments (two optical cavities made from ultralow...

The determination of salinity values from SI traceable densimetry and refractometry measurement results enable traceability the former. In this work, a short study metrological compatibility determinations via these two methods for sodium chloride in ultrapure water solutions different standard seawaters (OSIL ERM) solutions, [35.0; 215.0] g kg −1 interval, is presented. It evidenced referred i...

In the scope of miniaturized optical sensors for liquid refractometry, this work details the design, numerical simulation, and experimental characterization of a Fabry-Pérot resonator consisting of two deeply-etched silicon cylindrical mirrors with a micro-tube in between holding the liquid analyte under study. The curved surfaces of the tube and the cylindrical mirrors provide three-dimensiona...