Polarized Light Scattering Research Articles

Advancing the Understanding of Microplastic Weathering: Insights from a Novel Polarized Light Scattering Approach.

Weathering is a significant process that alters the properties of microplastics (MPs) and consequently affects their environmental behaviors. In this study, we introduced a novel approach based on polarized light scattering technique, which offers advantages in terms of rapid, high-throughput, and submicron-sized detection. This technique was successfully applied to characterize the weathered MPs after a 180-day laboratory simulation of coastal environments. By employing polarization measurements, we obtained a 46-dimensional matrix data set for the weathered MP fragments and subsequently processed them using a backpropagation neural network. The successful extraction of effective polarization pulses confirmed the presence of MP fragments within the size range of 0.2-60 μm, yielding total accuracies for size classification ranging from 78.9 to 86.9%. Furthermore, this technique achieved an overall accuracy of 93.8% in classifying MPs with different weathering degrees and polymer types, revealing polarization parameters associated with size and morphological changes play a dominant role in characterizing the weathering process of MPs. Compared with conventional approaches, the novel polarized light scattering approach holds great promise for rapid, high-throughput, and accurate characterization of MPs with small sizes. The findings of this study provided new insights into how MPs change after long-term weathering in aquatic environments.

Determination of Translational and Rotational Diffusivities of Anisotropic Nanoparticles by Heterodyne Polarized and Depolarized Dynamic Light Scattering

Determination of Translational and Rotational Diffusivities of Anisotropic Nanoparticles by Heterodyne Polarized and Depolarized Dynamic Light Scattering

Pulse Feature-Enhanced Classification of Microalgae and Cyanobacteria Using Polarized Light Scattering and Fluorescence Signals.

Harmful algal blooms (HABs) pose a global threat to the biodiversity and stability of local aquatic ecosystems. Rapid and accurate classification of microalgae and cyanobacteria in water is increasingly desired for monitoring complex water environments. In this paper, we propose a pulse feature-enhanced classification (PFEC) method as a potential solution. Equipped with a rapid measurement prototype that simultaneously detects polarized light scattering and fluorescence signals of individual particles, PFEC allows for the extraction of 38 pulse features to improve the classification accuracy of microalgae, cyanobacteria, and other suspended particulate matter (SPM) to 89.03%. Compared with microscopic observation, PFEC reveals three phyla proportions in aquaculture samples with an average error of less than 14%. In this paper, PFEC is found to be more accurate than the pulse-average classification method, which is interpreted as pulse features carrying more detailed information about particles. The high consistency of the dominant and common species between PFEC and microscopy in all field samples also demonstrates the flexibility and robustness of the former. Moreover, the high Pearson correlation coefficient accounting for 0.958 between the cyanobacterial proportion obtained by PFEC and the cyanobacterial density given by microscopy implies that PFEC serves as a promising early warning tool for cyanobacterial blooms. The results of this work suggest that PFEC holds great potential for the rapid and accurate classification of microalgae and cyanobacteria in aquatic environment monitoring.

Machine Learning Powered Microalgae Classification by Use of Polarized Light Scattering Data

Microalgae are widely distributed in the ocean, which greatly affects the ocean environment. In this work, a dataset is presented, including the polarized light scattering data of 35 categories of marine microalgae. To analyze the dataset, several machine learning algorithms are applied and compared, such as linear discrimination analysis (LDA) and two types of support vector machine (SVM). Results show that non-linear SVM performs the best among these algorithms. Then, two data preparation approaches for non-linear SVM are compared. Subsequently, more than 10 categories of microalgae out of the dataset can be identified with an accuracy greater than 0.80. The basis of the dataset is shown by finding the categories independent to each other. The discussions about the performance of different incident polarization of light gives some clues to design the optimal incident polarization of light for future instrumentation. With this proposed technique and the dataset, these microalgae can be well differentiated by polarized light scattering data.

Polarized Light Scattering of Particulate Matter in Detection of Oceanographic Profiling LiDAR

Polarized Light Scattering of Particulate Matter in Detection of Oceanographic Profiling LiDAR

Polarization State Variation Induced by the Circularly Polarized Light Scattering in LiNbO3：Fe Crystal（Invited）

Polarization State Variation Induced by the Circularly Polarized Light Scattering in LiNbO3：Fe Crystal（Invited）

Probing Individual Particles in Aquatic Suspensions by Simultaneously Measuring Polarized Light Scattering and Fluorescence.

Suspended particles play a significant role in aquatic systems. However, existing methods to probe suspended particles have several limitations. In this paper, we present a portable prototype to in situ probe individual particles in aquatic suspensions by simultaneously measuring polarized light scattering and fluorescence, aiming to obtain an effective classification of microplastics and microalgae. Results show that the obtained classification accuracy is significantly higher than that for either of these two methods. The setup also successfully measures submicron particles and discriminates two species of Synechococcus. Our study demonstrates the feasibility of simultaneously measuring polarized light scattering and fluorescence, and the promising capability of our method for further aquatic environmental monitoring.

In-situ Detection Method for Microplastics in Water by Polarized Light Scattering

Microplastics (MPs) have become the widespread contaminants, which raises concerns on their ecological hazards. In-situ detection of MP in water bodies is essential for clear assessment of the ecological risks of MPs. The present study proposes a method based on polarized light scattering which measures the polarization parameters of the scattered light at 120° to detect MP in water. This method takes the advantage of in-situ measurement of the individual particles and the experimental setup in principle is used. By use of the measured polarization parameters equipped by machine learning, the standard polystyrene (PS) spheres, natural water sample, and lab-cultured microalgae are explicitly discriminated, and MP with different physical and chemical properties can be differentiated. It can also characterize the weathering of different MP and identify the specific type from multiple types of MP. This study explores the capability of the proposed method to detect the physical and chemical properties, weathering state and concentration of MP in water which promises the future application in water quality sensing and monitoring.

Characterization of Intracellular Structure Changes of Microcystis under Sonication Treatment by Polarized Light Scattering.

Cyanobacterial bloom is one of the most urgent global environmental issues, which eventually could threaten human health and safety. Sonication treatment (ST) is a potential effective method to control cyanobacteria blooms in the field. Currently, the bottleneck of extensive application of ST is the difficulty to estimate the ST effect on the cyanobacterial cells and then determine suitable ST times in the field. In this study, cyanobacterial Microcystis samples sonicated at different times were first measured by a spectrophotometer to calculate the removal efficiency of Microcystis cells. Additionally, they were observed by TEM to reveal the intracellular structure changes of the cells. Then the samples were measured by an experimental setup based on polarized light scattering to measure the polarization parameters. Experimental results indicated that the polarization parameters can effectively characterize the intracellular structural changes of Microcystis cells with different ST times, which is quite consistent with the results for removal efficiency and TEM images. Further, the optimal ST time can be inferred by the polarization parameters. These results demonstrate that polarized light scattering can be a potentially powerful tool to explore suitable times for sonication treatment of cyanobacteria blooms.

Modeling of Chromatin DNA by Polarized Light Scattering

Polarized light scattering based techniques are non-invasive and label-free approaches allowing the description of physical parameters, such as size and molecular orientation of any kind of sample. More particularly, Mueller matrix polarimetry is a 4x4 elements mathematical tool which quantitatively describes the properties of sample from the measurements of scattered polarized light, such as the birefringence dichroism and scattering. The circular intensity differential scattering, S14 element of Mueller matrix, has been particularly reported to describe chiral properties of chromatin DNA. Recently, an experiment has been designed to measure the polarized light scattering images. In this way, we have acquired the absorption and scattering spectra of chromatin DNA organization at the single cellular level using polarized light scattering imaging, in the form of a Fourier (θ, φ) images. The topic of this presentation is to compare the acquired images with simulated ones from the Mie theory and the discrete dipole approximation (DDA). As a proof of principle of the calculation, simulations of scattering images of microspheres size were performed which demonstrated the correlation with the experimental results verifies the working of the technique. In a second step, DDA simulated images, combined with the experimental measurements of different population of cells demonstrate this technique as an interesting method to quantify biopolymers organization to micro- to nanoscopic scale.

Highly Sensitive Depolarized Light Scattering To Monitor Aggregation of Spherical Gold Nanoparticles

Aggregation of spherical gold nanoparticles (AuNPs) was monitored by simultaneous measurement of extinction, polarized light scattering (PLS), and depolarized light scattering (dPLS) spectra over t...

海洋背景下气溶胶的偏振光散射特性研究

海洋背景下气溶胶的偏振光散射特性研究

有核细胞对偏振光的散射强度分布

有核细胞对偏振光的散射强度分布

不同涂层对微粗糙基底的极化光散射影响

不同涂层对微粗糙基底的极化光散射影响

Tissue Self-Affinity and Polarized Light Scattering in the Born Approximation: A New Model for Precancer Detection

Light scattered from biological tissues can exhibit an inverse power law spectral component. We develop a model based on the Born approximation and von Karman (self-affine) spatial correlation of submicron tissue refractive index to account for this. The model is applied to light scattering spectra obtained from excised esophagi of normal and carcinogen-treated rats. Power law exponents used to fit dysplastic tissue site spectra are significantly smaller than those from normal sites, indicating that changes in tissue self-affinity can serve as a potential biomarker for precancer.

Size and Shape Prediction of Colloidal Metal Oxide MgBaFeO Particles from Light Scattering Measurements

The size and structure of colloidal metal oxide (MgBaFeO) particles are determined using an Elliptically Polarized Light Scattering (EPLS) technique. The approach is based on a hybrid experimental/theoretical study where the experimental data are compared against predictions obtained using a T-Matrix model that accounts for particle shape irregularities. A power-law distribution function with two parameters is employed to account for the particle size distribution. The refractive index of the particles in ethyl alcohol is calculated based on the Maxwell-Garnet formula. The experiments are conducted using a second-generation nephelometer. It is shown that the current EPLS measurements can effectively be used for identification of both the shape and the size of the colloids.

Polarized Light Scattering and Synchrotron Radiation Wide-Angle X-ray Diffraction Studies on Smectic Liquid Crystal Formation of Main-Chain Polyester

Polarized Light Scattering and Synchrotron Radiation Wide-Angle X-ray Diffraction Studies on Smectic Liquid Crystal Formation of Main-Chain Polyester

Polarized Light Scattering and Off-State Transmission of Electron-Beam Cured Polymer Dispersed Liquid Crystals

Polarized Light Scattering (LS) experiments are performed on thin Electron-Beam (EB) cured polymer precursor/liquid crystal (LC) films. The polarized component I vv is obtained for irradiated blends of a low molecular weight aromatic polyester acrylate, additional monomers like tripropyleneglycoldiacrylate, and the nematic LC mixture of cyanoparaphenylene derivatives known under the tradename E7 (Merck). The whole composition range between the pure cured polymer precursor and E7 was covered by exposing the corresponding initial samples to constant EB-curing conditions. Only the light scattering of polymer/LC films with no external fields is considered here and the results are compared with additional measurements of the optical off-state transmission. The results obtained from LS and transmission experiments are in excellent agreement.

Morphology and Mechanical Properties of Copolymer Ethylene−Methyl Methacrylate Films as a Function of Temperature Estimated by Polarized Light Scattering, X-ray, and 13C NMR

The relationship between the morphology and the mechanical properties of copolymer ethylene−methyl methacrylate (EMMA) was estimated as a function of temperature by using polarized light scattering, X-ray diffraction and 13C solid-state NMR. All of these measurements revealed unstable crystallites within the EMMA films having a MMA content >14 mol %, crystallinity less than 10%, and crystal size of about 3 nm. On the other hand, the ethylene sequences in the amorphous phase had an ordered arrangement rather than a random orientation. It is evident that these characteristics are due to the strong repulsion between MMA and ethylene. Namely, MMA side groups suppress the crystallization as an essential property of ethylene sequences; consequently, the difficulty of accelerating the self-arrangement of ethylene sequences as crystallites leads to a local ordered arrangement of long ethylene sequences in the amorphous phase. The maximum draw ratio of the EMMA film reached 10 times at room temperature. A specimen...

Structural analysis of G-DNA in solution: A combination of polarized and depolarized dynamic light scattering with hydrodynamic model calculations.

Specific intra- and intermolecular quadruplex conformations of model G-DNA oligonucleotides have been identified from their translational and rotational diffusion coefficients in aqueous solution. The transport properties were determined by polarized and depolarized dynamic light scattering. A comparison with hydrodynamic model calculations provides detailed information about the size and shape of the molecules and allows one to distinguish between alternative intra- and intermolecular association. The potential of this combination of methods to elucidate biomolecular structures in solution, to characterize conformational changes, and follow intermolecular interaction processes due to a response to external stimuli has been discussed.