The use of refractometers to investigate the nature of liquids is very common. Here it is shown that surface relief diffraction gratings can be used to measure the refractive index of liquids. Calibration plots showing the relation between first order intensity as a function of refractive index are shown. We also developed a microfluidic device behaving as a grating which is used as refractometer where a very small amount of liquid (microliters) is used.
In this work, several tests of the performance of 3,3’-thiodipropanol (TDP) as a mounting medium for fluorescence microscopy of biological samples were performed. Besides optical properties like the dispersion curve of TDP and the effect of the embedding medium on the fluorescence of commonly used dyes, the interaction with biological specimens, including the labeling of filamentous actin with fluorescent phalloidins, was tested: TDP showed to represent an interesting alternative to commercial mounting media. By mixing TDP with 2,2’-thiodiethanol (TDE), it was possible not only to fine tune the refractive index of the resulting solution, but to preserve the compatibility with fluorescent phalloidins.
The tympanic membrane (TM) is an important hearing component that when ruptured causes severe hearing difficulty. It has been mainly characterized mechanically by measuring its displacements, vibration modes, impedance, and thickness. The objective of this research is to determine the relationship of the TM’s thickness obtained with confocal laser scanning microscopy (with scans along the Z axis) with the magnitude of the TM’s surface displacements measured with sound stimuli of 1.8, 5.2, and 12 kHz using digital holographic interferometry. In order to correlate the data, three regions of four healthy cats’ TMs are studied, with a particular finding that the thickness is not the same in these regions and, among samples, a feature readily noticed in the magnitudes of the displacements. Through the relationship of the data from the TM’s surface displacements with its thickness, it is now possible to confidently detect pathological changes in its structure by simply quantifying the magnitude of the former, a characteristic corroborated by the Pearson correlation coefficient (r).