Fractal and Polarization Properties of Light Scattering Using Microcrystalline Pharmaceutical Aggregates

Fractal and polarization analysis of diffusively scattered light is applied to determine the complex relationship between fractal dimension of structural morphology and concentration of chemically active ingredients in two pharmaceutical mixture systems including a series of binary mixtures of acetaminophen in lactose and three multicomponent blends with a proprietary active ingredient. A robust approach is proposed to identify and filter out multiple- and single-scattering components of scattering indicatrix. The fractal dimension extracted from scattering field reveals complex structural details of the sample, showing strong dependence on low-dose drug concentration in the blend. Low-angle diffraction shows optical “halo” patterns near the angle of specular reflection caused by light refraction in microcrystalline aggregates. Angular measurements of diffuse reflection demonstrate noticeable dependence of Brewster's angle on drug concentration. It is shown that the acetaminophen microcrystals produce scattered light depolarization due to their optical birefringence. The light scattering measurement protocol developed for diffusively scattered light by microcrystalline pharmaceutical compositions provides a novel approach for the pattern recognition, analysis and classification of materials with a low concentration of active chemical ingredients.

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A Time-Resolved Low-Angle Light Scattering Apparatus. Application to Phase Separation Problems in Polymer Systems

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20010973 ◽

2001 ◽

Vol 66 (6) ◽

pp. 973-982 ◽

Cited By ~ 5

Author(s):

Čestmír Koňák ◽

Jaroslav Holoubek ◽

Petr Štěpánek

Keyword(s):

Phase Separation ◽

Light Scattering ◽

Signal To Noise Ratio ◽

Scattered Light ◽

Ccd Camera ◽

Time Resolved ◽

Polymer Systems ◽

Software Analysis ◽

Phase Separation Kinetics ◽

Small Angle Light Scattering

A time-resolved small-angle light scattering apparatus equipped with azimuthal integration by means of a conical lens or software analysis of scattering patterns detected with a CCD camera was developed. Averaging allows a significant reduction of the signal-to-noise ratio of scattered light and makes this technique suitable for investigation of phase separation kinetics. Examples of applications to time evolution of phase separation in concentrated statistical copolymer solutions and dissolution of phase-separated domains in polymer blends are given.

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Light-Scattering Simulations from Spherical Bimetallic Core–Shell Nanoparticles

Micromachines ◽

10.3390/mi12040359 ◽

2021 ◽

Vol 12 (4) ◽

pp. 359

Author(s):

Francesco Ruffino

Keyword(s):

Optical Properties ◽

Light Scattering ◽

Bimetallic Nanoparticles ◽

Dominant Role ◽

Scattered Light ◽

Specific Interaction ◽

Surface Enhanced Raman Spectroscopy ◽

Localized Surface Plasmon ◽

Core Shell ◽

The Core

Bimetallic nanoparticles show novel electronic, optical, catalytic or photocatalytic properties different from those of monometallic nanoparticles and arising from the combination of the properties related to the presence of two individual metals but also from the synergy between the two metals. In this regard, bimetallic nanoparticles find applications in several technological areas ranging from energy production and storage to sensing. Often, these applications are based on optical properties of the bimetallic nanoparticles, for example, in plasmonic solar cells or in surface-enhanced Raman spectroscopy-based sensors. Hence, in these applications, the specific interaction between the bimetallic nanoparticles and the electromagnetic radiation plays the dominant role: properties as localized surface plasmon resonances and light-scattering efficiency are determined by the structure and shape of the bimetallic nanoparticles. In particular, for example, concerning core-shell bimetallic nanoparticles, the optical properties are strongly affected by the core/shell sizes ratio. On the basis of these considerations, in the present work, the Mie theory is used to analyze the light-scattering properties of bimetallic core–shell spherical nanoparticles (Au/Ag, AuPd, AuPt, CuAg, PdPt). By changing the core and shell sizes, calculations of the intensity of scattered light from these nanoparticles are reported in polar diagrams, and a comparison between the resulting scattering efficiencies is carried out so as to set a general framework useful to design light-scattering-based devices for desired applications.

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Structural Morphology of Rabbit Patella and Suprapatella Cartilage by Microscopic MRI and Polarized Light Microscopy

Cartilage ◽

10.1177/1947603521990882 ◽

2021 ◽

pp. 194760352199088

Author(s):

Hannah Mantebea ◽

Syeda Batool ◽

Mouhamad Hammami ◽

Yang Xia

Keyword(s):

Articular Cartilage ◽

Light Microscopy ◽

Design Method ◽

Strong Dependence ◽

Polarized Light ◽

Polarized Light Microscopy ◽

Structural Morphology ◽

Pixel Resolution ◽

Patellar Cartilage ◽

Quantitative Results

Objective In order to appreciate the roles articular cartilage of sesamoid bones and sesamoid fibrocartilage play in anatomy and pathology, the articular cartilage of the patella ( n = 4) and suprapatella ( n = 4) (a sesamoid fibrocartilage) of 12 to 14 weeks old New Zealand rabbits were studied qualitatively and quantitatively. Design/Method The intact knee joints and block specimens from the joints were imaged using microscopic magnetic resonance imaging (µMRI) at a 97.6-µm pixel resolution for the former and 19.5-µm resolution for the latter. Histological sections were made out of the µMRI-imaged specimens, which were imaged using polarized light microscopy (PLM) at 0.25-, 1-, and 4-µm pixel resolutions. Results The patella cartilage varied in thickness across the medial to lateral ends of the sesamoid bone with the central medial aspect slightly thicker than the lateral aspect. The suprapatella fibrocartilage decreased proximally away from the knee joint. Quantitative results of patellar cartilage showed strong dependence of fiber orientation with the tissue depth. Three histological zones can be clearly observed, which are similar to articular cartilage from other large animals. The sesamoid fibrocartilage has one thin surface layer (10 µm thick) of parallel-arranged structured fibers followed immediately by the majority of random fibers in bulk tissue. T2 relaxation time anisotropy was observed in the patellar cartilage but not in the bulk fibrocartilage. Conclusion Given the different functions of these 2 different types of cartilages in joint motion, these quantitative results will be beneficial to future studies of joint diseases using rabbits as the animal model.

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Oil in Water Monitoring Using Advanced Light Scattering

ASME/USCG 2013 3rd Workshop on Marine Technology and Standards ◽

10.1115/mts2013-0301 ◽

2013 ◽

Author(s):

Gernot Seebacher ◽

Axel A. Schmidt ◽

Jochen Offermann

Keyword(s):

Light Scattering ◽

Oil Content ◽

Scattered Light ◽

Discharge Process ◽

Water Mixture ◽

Effluent Quality ◽

Light Pattern ◽

Bilge Water ◽

Oil In Water ◽

Wide Range

The paper provides background on how bilge water has changed over the years and how technology has enabled manufacturers to stay ahead of the curve by borrowing technological breakthroughs from other areas to the measurement of oil content in the marine environment. Light scattering provides today a universal and reliable method, able to measure the wide range of oils present in a wildly variable and unpredictable bilge water mixture. Bilge water regulations were put in place to reduce the potential of harm to the environment from oily bilge water discharges. Regulations require that instruments verify effluent quality continually during the discharge process, which precludes the adoption for shipboard use of standard laboratory style testing with the associated time delays to complete the analysis. Measuring oil content with the light scattering measuring instrument is a tried and tested means for compliant bilge water verification. State of the art instruments employ sophisticated light measuring systems and they use complex algorithms to convert the scattered light pattern values into oil content reading, thereby considering interference from other than oil suspended matter, they prevent harm to the environment from bilge water discharges. Paper published with permission.

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Aerosol light-scattering enhancement due to water uptake during the TCAP campaign

Atmospheric Chemistry and Physics ◽

10.5194/acp-14-7031-2014 ◽

2014 ◽

Vol 14 (13) ◽

pp. 7031-7043 ◽

Cited By ~ 42

Author(s):

G. Titos ◽

A. Jefferson ◽

P. J. Sheridan ◽

E. Andrews ◽

H. Lyamani ◽

...

Keyword(s):

Optical Properties ◽

Light Scattering ◽

Climate Models ◽

Single Scattering ◽

Mean Value ◽

Department Of Energy ◽

Cape Cod ◽

Hygroscopic Growth ◽

Aerosol Optical Properties ◽

Aerosol Parameters

Abstract. Aerosol optical properties were measured by the DOE/ARM (US Department of Energy Atmospheric Radiation Measurements) Program Mobile Facility during the Two-Column Aerosol Project (TCAP) campaign deployed at Cape Cod, Massachusetts, for a 1-year period (from summer 2012 to summer 2013). Measured optical properties included aerosol light-absorption coefficient (σap) at low relative humidity (RH) and aerosol light-scattering coefficient (σsp) at low and at RH values varying from 30 to 85%, approximately. Calculated variables included the single scattering albedo (SSA), the scattering Ångström exponent (SAE) and the scattering enhancement factor (f(RH)). Over the period of measurement, f(RH = 80%) had a mean value of 1.9 ± 0.3 and 1.8 ± 0.4 in the PM10 and PM1 fractions, respectively. Higher f(RH = 80%) values were observed for wind directions from 0 to 180° (marine sector) together with high SSA and low SAE values. The wind sector from 225 to 315° was identified as an anthropogenically influenced sector, and it was characterized by smaller, darker and less hygroscopic aerosols. For the marine sector, f(RH = 80%) was 2.2 compared with a value of 1.8 obtained for the anthropogenically influenced sector. The air-mass backward trajectory analysis agreed well with the wind sector analysis. It shows low cluster to cluster variability except for air masses coming from the Atlantic Ocean that showed higher hygroscopicity. Knowledge of the effect of RH on aerosol optical properties is of great importance for climate forcing calculations and for comparison of in situ measurements with satellite and remote sensing retrievals. In this sense, predictive capability of f(RH) for use in climate models would be enhanced if other aerosol parameters could be used as proxies to estimate hygroscopic growth. Toward this goal, we propose an exponential equation that successfully estimates aerosol hygroscopicity as a function of SSA at Cape Cod. Further work is needed to determine if the equation obtained is valid in other environments.

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Evaluating biases in filter-based aerosol absorption measurements using photoacoustic spectroscopy

Atmospheric Measurement Techniques ◽

10.5194/amt-12-3417-2019 ◽

2019 ◽

Vol 12 (6) ◽

pp. 3417-3434 ◽

Cited By ~ 13

Author(s):

Nicholas W. Davies ◽

Cathryn Fox ◽

Kate Szpek ◽

Michael I. Cotterell ◽

Jonathan W. Taylor ◽

...

Keyword(s):

Biomass Burning ◽

Photoacoustic Spectroscopy ◽

Strong Dependence ◽

Single Scattering ◽

Aerosol Absorption ◽

Aerosol Mass ◽

Correction Scheme ◽

Measurement Biases ◽

Absorption Photometer ◽

Absorption Measurements

Abstract. Biases in absorption coefficients measured using a filter-based absorption photometer (Tricolor Absorption Photometer, or TAP) at wavelengths of 467, 528 and 652 nm are evaluated by comparing to measurements made using photoacoustic spectroscopy (PAS). We report comparisons for ambient sampling covering a range of aerosol types including urban, fresh biomass burning and aged biomass burning. Data are also used to evaluate the performance of three different TAP correction schemes. We found that photoacoustic and filter-based measurements were well correlated, but filter-based measurements generally overestimated absorption by up to 45 %. Biases varied with wavelength and depended on the correction scheme applied. Optimal agreement to PAS data was achieved by processing the filter-based measurements using the recently developed correction scheme of Müller et al. (2014), which consistently reduced biases to 0 %–18 % at all wavelengths. The biases were found to be a function of the ratio of organic aerosol mass to light-absorbing carbon mass, although applying the Müller et al. (2014) correction scheme to filter-based absorption measurements reduced the biases and the strength of this correlation significantly. Filter-based absorption measurement biases led to aerosol single-scattering albedos that were biased low by values in the range 0.00–0.07 and absorption Ångström exponents (AAEs) that were in error by ± (0.03–0.54). The discrepancy between the filter-based and PAS absorption measurements is lower than reported in some earlier studies and points to a strong dependence of filter-based measurement accuracy on aerosol source type.

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Sequential Extraction of Late Exponentials (SELE): A technique for deconvolving multimodal correlation curves in Dynamic Light Scattering

MRS Advances ◽

10.1557/adv.2020.163 ◽

2020 ◽

Vol 5 (17) ◽

pp. 865-880 ◽

Cited By ~ 2

Author(s):

Preethi L Chandran

Keyword(s):

Light Scattering ◽

Dynamic Light Scattering ◽

Sequential Extraction ◽

Time Scales ◽

Scattered Light ◽

Correlation Spectroscopy ◽

Least Square ◽

Multiple Time Scales ◽

Multiple Time ◽

Correlation Curve

Abstract:In techniques such as Dynamic Light Scattering (DLS), Fluorescence Correlation Spectroscopy, and image mining, motion is tracked by the autocorrelation of a signal over logarithmic time scales. For instance the tracking signal in DLS is the scattered light intensity; it remains correlated at time scales where scant changes in the arrangement of the scattering particles occur, but decays exponentially at the time scales of their diffusion. When there are multiple time scales of motion (for instance due to scatterers of different sizes), the correlation curve has more than one exponential fall. Extracting the decay constants or hydrodynamic sizes due to each exponential fall in a multi-species field correlation curve becomes an ill-conditioned mathematical problem. We describe a new algorithm to invert a multi-modal correlation curve by Sequential Extraction of the Late Exponentials (SELE). The idea is that while the inversion of a multi-exponential equation may be ill posed, that of a single exponential is not. So we fit data windows towards to base of the correlation curve to extract the largest contribution species, remove the species contribution from the correlation curve, and repeat the process with the remnant curve. The single exponent can be robustly fitted by least-square minimization with initial guesses generated by an adapted cumutant technique (power-series) that includes stretch coefficients (measure of sample dispersity). The proposed algorithm resolves particle sizes separated by 3X, and is reliable against fluctuations in the correlation curve and to localized regions of suboptimal data. The algorithm can be used to track particle dynamics in solution in multi-species problems such as self-assembly.

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