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Development and evaluation of realistic optical cell models for rapid and label-free cell assay by diffraction imaging
摘要： Methods for rapid and label-free cell assay are highly desired in life science. Single-shot diffraction imaging presents strong potentials to achieve this goal as evidenced by past experimental results using methods such as polarization diffraction imaging flow cytometry. We present here a platform of methods toward solving these problems and results of optical cell model (OCM) evaluations by calculations and analysis of cross-polarized diffraction image (p-DI) pairs. Four types of realistic OCMs have been developed with two prostate cell structures and adjustable refractive index parameters to investigate the effects of cell morphology and index distribution on calculated p-DI pairs. Image patterns have been characterized by a gray-level co-occurrence matrix (GLCM) algorithm and 4 GLCM parameters and linear depolarization ratio δL have been selected to compare calculated against measured data of prostate cells. Our results show that the irregular shapes of and heterogeneity in refractive index (RI) distributions for organelles play significant roles in the spatial distribution of scattered light by cells in comparison to the average RI values and their differences among the organelles. Discrepancies in GLCM and δL parameters between calculated and measured p-DI data provide useful insight for understanding light scattering by single cells and improving OCM.
关键词： cell models,light scattering,diffraction imaging,cell analysis
更新于2025-09-10 09:29:36
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Wave Propagation Concepts for Near-Future Telecommunication Systems || Light Wave Propagation and Scattering Through Particles
摘要： The study of light propagating and scattering for various particles has always been important in many practical applications, such as optical diagnostics for combustion, monitoring of atmospheric pollution, analysis of the structure and pathological changes of the biological cell, laser Doppler technology, and so on. This chapter discusses propagation and scattering through particles. The description of the solution methods, numerical results, and potential application of the light scattering by typical particles is introduced. The generalized Lorenz-Mie theory (GLMT) for solving the problem of Gaussian laser beam scattering by typical particles with regular shapes, including spherical particles, spheroidal particles, and cylindrical particles, is described. The numerical methods for the scattering of Gaussian laser beam by complex particles with arbitrarily shape and structure, as well as random discrete particles are introduced. The essential formulations of numerical methods are outlined, and the numerical results for some complex particles are also presented.
关键词： Gaussian laser beam,generalized Loren-Mie theory,light scattering,numerical method,small particles
更新于2025-09-09 09:28:46
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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - Nonlinear Optical Phenomena in Silicon-Smectic A Liquid Crystal (SALC) Waveguiding Structures
摘要： Liquid crystals (LCs) are organic materials characterized by a certain degree of ordering and anisotropy in their fluido-dynamic, elastic and electromagnetic properties. LCs possess strong optical nonlinearity. Due to these unique properties, LCs are promising candidates for the development of novel integrated devices for telecommunications and sensing. Nematic liquid crystals (NLCs) are mostly used and studied. However, smectic A liquid crystals (SALCs) have a higher degree of long range order, lower scattering losses in SALC, and they can be useful in nonlinear optical applications. We theoretically studied the nonlinear optical phenomena in a Silicon-SALC waveguide. We have shown that the strong stimulated light scattering (SLS) caused by SALC nonlinearity can occur in the Silicon-SALC waveguide.
关键词： silicon photonics,optical waveguide,stimulated light scattering,smectic A liquid crystal (SALC)
更新于2025-09-09 09:28:46
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Hydroxypropyl Methacrylate Interaction and Chitosan Coating for Enhanced UV Detection Sensitivity of Colloidal Nanoparticles in Capillary Electrophoresis Analysis
摘要： The binding interactions between silica (SiO2), titania (TiO2) or polymeric nanoparticles with hydroxypropyl methacrylate (HPMA) were investigated for enhancing the ultraviolet (UV) detection sensitivity of these nanoparticles in capillary electrophoresis (CE) analysis. HPMA interacted with colloidal SiO2 nanoparticles, producing a larger CE-UV peak at a slightly shorter migration time. An increase in particle size with HPMA binding was validated using dynamic light scattering. The interaction was selective as HPMA did not interact with TiO2 nanoparticles in aqueous suspension. Chitosan coating of SiO2 or TiO2 nanoparticles produced significantly larger hydrodynamic diameters to further enhance the sensitivity of their UV detection. The analytical technique, which involves coating SiO2 nanoparticles with chitosan first and binding with HPMA next, is novel. It has allowed us to achieve a significant enhancement of 50 folds in detection sensitivity.
关键词： Titania,Colloid,Nanoparticles,Capillary electrophoresis,Chitosan,Hydroxypropyl methacrylate,Silica,Polymer,Dynamic light scattering
更新于2025-09-09 09:28:46
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Photophysics at Unusually High Dye Concentrations
摘要： The study of the interaction of light with systems at high dye concentrations implies a great challenge because several factors, such as emission reabsorption, dye aggregation, and energy trapping, hinder rationalization and interpretation of the involved photophysical processes. Space constraints induce dye interaction even in the absence of ground state stabilization of dimers and oligomers. At distances on the order of 1 nm, statistical energy traps are usually observed. At longer distances, excited state energy transfer takes place. Most of these factors do not result in ground state spectroscopic changes. Rather, fluorescence phenomena such as inner filter effects, concentration-dependent Stokes’ shifts, and changes in quantum yields and decay times are evidenced. Photophysical studies are commonly carried out at high dilution, to minimize dye?dye interactions and emission reabsorption, and in the absence of light scattering. Under these conditions, the system becomes rather simple. Fluorescence and triplet quantum yields become molecular properties and can be easily related to ratios of rate constants. However, many systems containing dyes able to fulfill specific functions, whether man-made or biological, are far from being dilute and scattering-free. The photosynthetic apparatus is a paradigmatic example. It is clear that isolation of components allows gathering relevant information about complex systems. However, knowledge of the photophysical behavior in the unaltered environment is essential in most cases. Complexity generally increases when light scattering is present. Despite that, our experience shows that light scattering, when correctly handled, may even simplify the task of unraveling molecular parameters. We show that methods and models aiming at the determination and interpretation of fluorescence and triplet quantum yields as well as energy transfer efficiencies can be developed on the basis of simple light-scattering theories. Photophysical studies were extended to thin films and layer-by-layer assemblies. Procedures are presented for the evaluation of fluorescence reabsorption in concentrated fluid solutions up to the molar level, which are being applied to ionic liquids, in which the emitting species are the bulk ions. Fluorescence reabsorption models proved to be useful in the interpretation of the photophysics of living organisms such as plant leaves and fruits. These new tools allowed the assessment of chlorophyll fluorescence at the chloroplast, leaf and canopy levels, with implications in remote sensing and the development of nondestructive optical methods.
关键词： light scattering,dye concentrations,photophysics,fluorescence reabsorption,energy transfer
更新于2025-09-09 09:28:46
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Estimation of the particle size distribution of colloids from multiangle dynamic light scattering measurements with particle swarm optimization
摘要： In this paper particle Swarm Optimization (PSO) algorithms are applied to estimate the particle size distribution (PSD) of a colloidal system from the average PSD diameters, which are measured by multi-angle dynamic light scattering. The system is considered a nonlinear inverse problem, and for this reason the estimation procedure requires a Tikhonov regularization method. The inverse problem is solved through several PSO strategies. The evaluated PSOs are tested through three simulated examples corresponding to polystyrene (PS) latexes with different PSDs, and two experimental examples obtained by simply mixing 2 PS standards. In general, the evaluation results of the PSOs are excellent; and particularly, the PSO with the Trelea’s parameter set shows a better performance than other implemented PSOs.
关键词： inverse problem,particle swarm optimization algorithm,particle size distribution,Swarm Intelligence,dynamic light scattering
更新于2025-09-09 09:28:46
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Design of indoor dust concentration monitor based on light scattering detection method
摘要： Inhalable particles and fine particulates in dust will pollute the indoor environment and endanger people's health. It is an important task to take effective measures to control indoor dust pollution. The key is to keep abreast of the dust concentration, and to monitor, control and evaluate the sources of indoor dust pollution. This paper analyzes the main sources and characteristics of indoor dust and uses dust sensor to collect dust and transform photoelectric signals. It applies micro control unit (MCU) to control the system and process data, and designs the dust concentration monitor. The monitor can be used as an independent equipment and also a combination of a variety of sensors through the serial port to monitor indoor environmental parameters and control environmental control facilities, thereby purifying indoor air.
关键词： micro control unit (MCU),dust,Light scattering,dust sensors
更新于2025-09-09 09:28:46
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Effect of Glistening-Free Intraocular Lens on Intraocular Straylight
摘要： Purpose: To compare intraocular straylight between glistening-free and conventional intraocular lenses in pseudophakic eyes. Methods: Straylight values were measured prospectively in 21 eyes with glistening-free pseudophakic lenses (group A, model enVista?, Bausch & Lomb, Inc., USA) and 79 eyes with conventional hydrophilic pseudophakic lenses (group B, model Akreos MI-60, Bausch & Lomb, Inc., USA). Best corrected visual acuity (BCVA) and straylight were measured preoperatively and 1 month and 2 months postoperatively using C-quant straylight meter (Oculus GmbH, Wetzlar, Germany). Results: There were no statistically significant differences of BCVA preoperatively or 2 months postoperatively between the 2 groups (p > 0.05). BCVA and straylight significantly improved after the operation (p < 0.05). The mean straylight values were 1.43 ± 0.12 (log[s]) and 1.41 ± 0.16 (log[s]) for group A, and 1.33 ± 0.61 (log[s]) and 1.40 ± 0.82 (log[s]) for group B at postoperative 1 month and 2 months, respectively, with no statistical significance between the 2 groups (p > 0.05). Conclusions: In terms of straylight, glistening-free intraocular lenses were not beneficial. Although straylight was not statistically significant, other correlations between glistening and visual function should be investigated.
关键词： Light scattering,Glistening,Straylight
更新于2025-09-09 09:28:46
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A Versatile Dynamic Light Scattering Strategy for the Sensitive Detection of Plant MicroRNAs Based‐on Click Chemistry‐Amplified Aggregation of Gold Nanoparticles
摘要： Plant microRNAs (miRNAs) are naturally 2′-O-methylated at the 3′-terminal, so they cannot be efficiently detected by traditional target-triggered polymerization reactions. Herein, a simple but robust enzyme-free sensing strategy is developed for plant miRNA analysis by using dynamic light scattering (DLS) technique to monitor the click chemical ligation-amplified crosslinking of gold nanoparticles (AuNPs). Combining the enzyme-free cycling chemical ligation-mediated signal amplification, and the intrinsic outstanding ability of DLS for discriminating the extremely low level of particle aggregation in a large pool of monodisperse AuNPs, high sensitivity is achieved and as low as 78.6 fM plant miRNA can be easily detected.
关键词： crosslinking,click chemistry,plant microRNA,dynamic light scattering (DLS),gold nanoparticles
更新于2025-09-09 09:28:46
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Characterizing the size and absorption of single nonspherical aerosol particles from angularly-resolved elastic light scattering
摘要： Measuring the absorption of a single aerosol particle is a challenging endeavor. Of the few techniques available, none are suitable for measuring the single-particle absorption of coarse-mode nonspherical aerosols. Analysis of two-dimensional angular optical scattering (TAOS) patterns provide a possible pathway to perform this measurement. Using a Multiple-Sphere T-Matrix (MSTM) code, we simulate the captured TAOS patterns with geometries similar to a previously designed instrument. By analyzing the size of the speckle and the integrated irradiance of these simulated TAOS patterns, we are able to distinguish between high-absorbing, weak-absorbing, and non-absorbing particles over the size range of 2μm to 10μm. In particular, the speckle present in the scattering patterns provides a means to estimate the size of the particle. Once the size of the particle is known, the integrated irradiance provides insight into the absorption of the particle.
关键词： Absorption,Elastic Light Scattering,Aerosol,Single Particle
更新于2025-09-09 09:28:46