Fluorescence Anisotropy as a Temperature-Sensing Molecular Probe Using Fluorescein

Fluorescence anisotropy, a technique to study the folding state of proteins or affinity of ligands, is used in this present work as a temperature sensor, to measure the microfluidic temperature field, by adding fluorophore in the liquid. Fluorescein was used as a temperature-sensing probe, while glycerol–aq. ammonia solution was used as a working fluid. Fluorescence anisotropy of fluorescein was measured by varying various parameters. Apart from this, a comparison of fluorescence anisotropy and fluorescence intensity is also performed to demonstrate the validity of anisotropy to be applied in a microfluidic field with non-uniform liquid thickness. Viscosity dependence and temperature dependence on the anisotropy are also clarified; the results indicate an appropriate selection of relation between molecule size and viscosity is important to obtain a large temperature coefficient in anisotropy. Furthermore, a practical calibration procedure of the apparatus constant is proposed. In addition, the potential of temperature imaging is confirmed by the measurement of temperature distribution under focused laser heating.

A Cell’s Viscoelasticity Measurement Method Based on the Spheroidization Process of Non-Spherical Shaped Cell

The mechanical properties of biological cells, especially the elastic modulus and viscosity of cells, have been identified to reflect cell viability and cell states. The existing measuring techniques need additional equipment or operation condition. This paper presents a cell’s viscoelasticity measurement method based on the spheroidization process of non-spherical shaped cell. The viscoelasticity of porcine fetal fibroblast was measured. Firstly, we introduced the process of recording the spheroidization process of porcine fetal fibroblast. Secondly, we built the viscoelastic model for simulating a cell’s spheroidization process. Then, we simulated the spheroidization process of porcine fetal fibroblast and got the simulated spheroidization process. By identifying the parameters in the viscoelastic model, we got the elasticity (500 Pa) and viscosity (10 Pa·s) of porcine fetal fibroblast. The results showed that the magnitude of the elasticity and viscosity were in agreement with those measured by traditional method. To verify the accuracy of the proposed method, we imitated the spheroidization process with silicone oil, a kind of viscous and uniform liquid with determined viscosity. We did the silicone oil’s spheroidization experiment and simulated this process. The simulation results also fitted the experimental results well.

Waveguide amplification of dye fluorescece in NLC

The amplification of spontaneous fluorescence in a planar layer of a nematic liquid crystal doped with a DCM dye is experimentally studied in a waveguide mode of light propagation. The optical pumping threshold of the superfluorescence is 0.65 MW/cm2. The gain value reaches 0.0014 μm-1 at a pumping intensity of 1.38 MW/cm2. Full Text: PDF ReferencesLiquid Crystal Microlasers, Eds. L. M. Blinov, R. Bartolino (Kerala India, Transworld Research Network 2010). DirectLink H. Kogelnik, C. V. Shank, "Coupled‐Wave Theory of Distributed Feedback Lasers", J. Appl. Phys. 43, 2327 (1972). CrossRef I. P. Il'chishin, E. A. Tihonov, V. G. Tishchenko, M. T. Shpak, "Generation of a tunable radiation by impurity cholesteric liquid crystals", JETP Lett. 32, 25 (1980). DirectLink A. Yariv, M. Nakamura, "Periodic structures for integrated optics", IEEE Quant. Electr. 13, 233 (1977). CrossRef N. M. Shtykov, M. I. Barnik, L. M. Blinov B. A. Umanskii, S, P. Palto, "Amplification of the emission of a liquid-crystal microlaser by means of a uniform liquid-crystal layer", JETP Lett. 85, 602 (2007). CrossRef

Wastewaters Pollution Control Using Two-Frequency Laser Sounding

Optical methods for analysis of non-uniform liquid mediums have been considered, correlational and functional connections between the optical density and parameters characterizing industrial wastewaters’ type, content and pollution level have been investigated. Have been demonstrated main tendencies related to development of technology and equipment for optoelectronic control of industrial wastewaters’ pollution. Approximation of emission and absorption spectra for optical radiation’s emitter and receiver using the known Laplace function allows carry out calculations for a choice of optical couples’ coordinated parameters for two-frequency optical control, and as a result to increase reliability of identification for a type and degree of pollution for wastewaters and industrial effluents in comparison with use of one emission source. The method of pollution two-frequency laser sounding differs in improved control characteristics compared with the ones offered in patents, as well as in scientific and technical literature.