Scattered light imaging beyond the memory effect using the dynamic properties of thick turbid media

Scattered light imaging through complex turbid media has significant applications in biomedical and optical research.For the past decade,various approaches have been proposed for rapidly reconstructing fullcolor,depth-extended images by introducing point spread functions(PSFs).However,because most of these methods consider memory effects(MEs),the PSFs have angular shift invariance over certain ranges of angles.This assumption is valid for only thin turbid media and hinders broader applications of these technologies in thick media.Furthermore,the time-variant characteristics of scattering media determine that the PSF acquisition and image reconstruction times must be less than the speckle decorrelation time,which is usually difficult to achieve.We demonstrate that image reconstruction methods can be applied to timevariant thick turbid media.Using the time-variant characteristics,the PSFs in dynamic turbid media within certain time intervals are recorded,and ergodic scattering regimes are achieved and combined as ensemble point spread functions(ePSFs).The ePSF traverses shift-invariant regions in the turbid media and retrieves objects beyond the ME.Furthermore,our theory and experimental results verify that our approach is applicable to thick turbid media with thickness of 1 cm at visible incident wavelengths.

Mechanisms of ultrasonic modulation of multiply scattered incoherent light based on diffusion theory

An analytic equation interpreting the intensity of ultrasound-modulated scattering light is derived, based on diffusion theory and previous explanations of the intensity modulation mechanism. Furthermore, an experiment of ultrasonic modulation of incoherent light in a scattering medium is developed. This analytical model agrees well with experimental results,which confirms the validity of the proposed intensity modulation mechanism. The model supplements the existing research on the ultrasonic modulation mechanism of scattering light.

In-Situ Measuring the Particle Mean Size and Dust Concentration by Near-Forward Small Angle Light Scattering

This paper presents a method of measuring the particle mean size and dust concentration by small angle near forward light scattering optics and the extinction theory. Its theory is based on Fraunhofer diffraction theory which is the approximation of Mie scattering within the forward Fraunhofer diffraction lobe, and Rosin Rammler function is introduced to describe the particle size distribution in two phase flow in advance. Compared with the values by the sample weight method, the measurement results have a reasonable agreement. The present work has demonstrated that this method will be probably used to monitor the parameters of two phase flow.

Application of L-Cys-Capped CdS Nanoparticles in Determination of Nucleic Acid by Resonance Light-Scattering Technique

Aim To determine nucleic acid （DNA） using Nanometer-sized L-cysteine-capped CdS particles by resonance light scattering （RLS） method. Methods The nano-particles synthesized by a colloidal aqueous method were water-soluble, stable, and highly luminescent. The RLS of L-Cys-CdS particles were greatly quenched by DNA in Tris-HCl solutions. The intensity of RLS at 344 nm was proportional to the concentration of DNA. Results The linearity range of the calibration curve was 0. 01 - 1.0 μg·mL^-1 for calf thymus DNA and 0. 04 - 1.5 μg· mL^-1 for salmon sperm DNA. The detection limits （3 δ） were 8 ng·mL^-1 for calf thymus DNA and 10 ng·mL^-1 for salmon sperm DNA. Conclusion This method is simple, sensitive, and capable of avoiding the use of toxic dyes.

On the Radiative Properties of Ice Clouds:Light Scattering, Remote Sensing,and Radiation Parameterization

Presented is a review of the radiative properties of ice clouds from three perspectives： light scattering simulations, remote sensing applications, and broadband radiation parameterizations appropriate for numerical models. On the subject of light scattering simulations, several classical computational approaches are reviewed, including the conventional geometric-optics method and its improved forms, the finite-difference time domain technique, the pseudo-spectral time domain technique, the discrete dipole approximation method, and the T-matrix method, with specific applications to the computation of the singlescattering properties of individual ice crystals. The strengths and weaknesses associated with each approach are discussed.With reference to remote sensing, operational retrieval algorithms are reviewed for retrieving cloud optical depth and effective particle size based on solar or thermal infrared（IR） bands. To illustrate the performance of the current solar- and IR-based retrievals, two case studies are presented based on spaceborne observations. The need for a more realistic ice cloud optical model to obtain spectrally consistent retrievals is demonstrated. Furthermore, to complement ice cloud property studies based on passive radiometric measurements, the advantage of incorporating lidar and/or polarimetric measurements is discussed.The performance of ice cloud models based on the use of different ice habits to represent ice particles is illustrated by comparing model results with satellite observations. A summary is provided of a number of parameterization schemes for ice cloud radiative properties that were developed for application to broadband radiative transfer submodels within general circulation models（GCMs）. The availability of the single-scattering properties of complex ice habits has led to more accurate radiation parameterizations. In conclusion, the importance of using nonspherical ice particle models in GCM simulations for climate studies is proven.

Light-scattering model for aerosol particles with irregular shapes and inhomogeneous compositions using a parallelized pseudo-spectral time-domain technique

To improve the modeling accuracy of radiative transfer,the scattering properties of aerosol particles with irregular shapes and inhomogeneous compositions should be simulated accurately.To this end,a light-scattering model for nonspherical particles is established based on the pseudo-spectral time domain(PSTD)technique.In this model,the perfectly matched layer with auxiliary differential equation(ADE-PML),an excellent absorption boundary condition(ABC)in the finite difference time domain generalized for the PSTD,and the weighted total field/scattered field(TF/SF)technique is employed to introduce the incident light into 3 D computational domain.To improve computational efficiency,the model is further parallelized using the Open MP technique.The modeling accuracy of the PSTD scheme is validated against Lorenz–Mie,Aden–Kerker,T-matrix theory and DDA for spheres,inhomogeneous particles and nonspherical particles,and the influence of the spatial resolution and thickness of ADE-PML on the modeling accuracy is discussed as well.Finally,the parallel computational efficiency of the model is also analyzed.The results show that an excellent agreement is achieved between the results of PSTD and well-tested scattering models,where the simulation errors of extinction efficiencies are generally smaller than 1%,indicating the high accuracy of our model.Despite its low spatial resolution,reliable modeling precision can still be achieved by using the PSTD technique,especially for large particles.To suppress the electromagnetic wave reflected by the absorption layers,a six-layer ADE-PML should be set in the computational domain at least.

Light Focusing through Scattering Media by Particle Swarm Optimization

We demonstrate light focusing through scattering media by introducing particle swarm optimization for modulat- ing the phase wavefront. Light refocusing is simulated numerically based on the angular spectrum method and the circular Gaussian distribution model of the scattering media. Experimentally, a spatial light modulator is used to control the phase of incident light, so as to make the scattered light converge to a focus. The influence of divided segments of input light and the effect of the number of iterations on light intensity enhancement are investigated. Simulation results are found to be in good agreement with the theoretical analysis for light refocusing.

Quantification of six bioactive compounds in Zhenqi Fuzheng preparation by high-performance liquid chromatography coupled with diode array detector and evaporative light scattering detector

A simple and accurate high-performance liquid chromatography（HPLC）coupled with diode array detector（DAD）and evaporative light scattering detector（ELSD）was established for the determination of six bioactive compounds in Zhenqi Fuzheng preparation（ZFP）.The monitoring wavelengths were 254,275 and 328 nm.Under the optimum conditions,good separation was achieved,and the assay was fully validated in respect of precision,repeatability and accuracy.The proposed method was successfully applied to quantify the six ingredients in 31 batches of ZFP samples and evaluate the variation by hierarchical cluster analysis（HCA）,which demonstrated significant variations on the content of these compounds in the samples from different manufacturers with different preparation procedures.The developed HPLC method can be used as a valid analytical method to evaluate the intrinsic quality of this preparation.

Selective Determination of Nanogram γ-Globulin in Human Blood Serum by Resonance Light Scattering of Functionalized NanoPbS

Functionalized nano-PbS has been prepared and characterized. The functionalized nanoparticles have good dispersibility in water. Reaction of functionalized nanoPbS with gglobulin (gIgG) results an enhanced resonance light scattering (RLS) around 385 nm. However, when the content of HSA is lower than 0.5 mg ml-1 the RLS enhancement is very weak and is nonlinear to concentration of HSA. Based on these results, a new direct quantitative determination method for gglobulin in blood serum samples without separation is established. Under optimal conditions, the enhanced RLS intensity is in proportion to the gIgG concentration in the range 10500 ng/mL. The limit of detection is 2.75 ng/mL. This method is proved to be very sensitive, rapid, simple and selective for detection of gIgG in blood serum.

Characterization of gold nanoparticle bioconjugation by resonance light scattering correlation spectroscopy

Gold nanoparticles （GNPs） have been widely used as probes and nanomaterials in certain biological and biomedical fields thanks to its special physical and chemical properties. However, it is still difficult to characterize GNPs-bioconjugates in solution, which has greatly limited further bioapplications of GNPs. In this study, we reported a single particle method for characterizing GNPs- biomolecules in solution using resonance light scattering correlation spectroscopy （RLSCS）. The interaction of GNPs with bovine serum albumin （BSA） and thiol-modified oligonucletides were investigated.

Resonance Light Scattering Spectra of Silver Thiocyanate System and its Application in Analysis

A novel determination method of Ag^＋ was established. In acetic acid-sodium acetate buffer （pH 5.0） medium, Ag^＋ reacts with SCN^- to form AgSCN in the presence of TritonX-100,which results in an increase of resonance light scattering （RLS）and giving a new RLS spectrum.The maximum RLS peak was at 585 nm,The enhancement of resonance light scattering at 585 nm was proportional to the concentration of Ag^＋ ranging from 0.0045-4.00μg mL^-1 （r=9991）,and the detection limit was 1.37 ng mL^-1 with the recovery of 97.70%- 104.80%。

Comparison of pseudophakic retinal straylight in spherical/aspherical and hydrophobic/hydrophilic intraocular lens

AIM: To study the potential reasons of increased straylight in pseudophakic eyes. METHODS: Cross -sectional study. Seventy patients diagnosed as bilateral age-related cataract and implanted with Tecnis ZA9003, Sensar AR40e, SA6OAT, XLSTABI ZO or Akeros AO intraocular lens (IOL) were enrolled in this research. Straylight was measured by a C -Quant straylight meter three to four weeks postoperatively. Five different modalities of IOL, including spherical/aspherical optics and hydrophobic/hydrophilic material were tested in this study. Normal as well as dilated pupils were used. The main outcome variable for straylight measurement was the logarithmic straylight parameter, log(s). RESULTS: The straylight parameter increased significantly after pupil dilation (P<0.05). Straylight of aspherical IOL was significantly higher after pupil dilation (P<0.06) compared to spherical IOL. In normal pupil, straylight of hydrophobic IOL was significant higher when compared with hydrophilic IOL (P<0.05). CONCLUSION: Straylight and visual acuity stand for the different aspects of visual function. Several factors including pupil diameter, optic material, aspherical design of IOL influence intraocular light scattering in pseudophakic eyes. Further investigation was needed to study the impact of optic material and optic surface design on pseudophakic straylight.

COMPOSITION DETERMINATION OF BINARY POLYMER MIXTURES BY SIZE EXCLUSION CHROMATOGRAPHY WITH LIGHT SCATTERING DETECTION

Base on the principle of absolute quantification of size exclusion chromatography （SEC）, a light scattering （LS） detector coupled with a concentration detector （refractive index detector） is utilized to determine the compositions of complicated binary mixtures. A theoretical analysis predicts that the response factors for both LS and RI detectors are linear functions with the composition of any specified polymer mixtures in the binary polymer mixtures. Two pairs of complicated binary mixtures were used to test the theory mentioned in the present paper, and the experimental results show an excellent accordance with the theory.

Resonance Light Scattering Imaging Determination of Heparin

A laser-induced resonance light scattering （RLS） imaging method to determine heparin is described based on the high light scattering emission power of the aggregation species of heparin with α, β, γ, δ-tetra（4-trimethylaminoniumphenyl）prophyrin （TAPP） in solution, By imaging the light scattering signals of the aggregation species, we proposed the method to determine the heparin with a detection range of 0.02 - 0.6μg/mL and the detection limit （30） of 1.3 ng/mL.

Solution Properties of Mixed Starch/Chitosan Revealed by Resonance Light Scattering

The association behavior of starch and chitosan and the dilute solution properties of the starch/chitosan complex were investigated by means of resonance light scattering（RLS） spectra.The interaction between starch and chiotsan was proved by RLS.Based on the results,the appropriate association condition was selected.However,the solution property of starch/chitosan was affected greatly by external factors such as pH value and metal ionic strength.The change of pH,which causes the irreversible transition of solution from transparent into murky,provides some important information of partitioning behavior of the complex in solution.The durative enhancement of RLS intensity for the complex exhibited two inflexions and a plateau in the presence of a certain amount of Fe 3＋.It indicates that Fe 3＋ not only increases the RLS intensity,but also induces the micell-aggregate transition of the complex in solution.Moreover,the thermodynamic parameters for micell formation process at different temperatures,based on the RLS values,were calculated.

Light scattering by a spherical particle with multiple densely packed inclusions

This paper calculates light scattering by a spherical water particle containing densely packed inclusions at a visible wavelength 0.55 μm by a combination of ray-tracing and Monte Carlo techniques. While the individual reflection and refraction events at the outer boundary of a sphere particle are considered by a ray-tracing program, the Monte Carlo routine simulates internal scattering processes. The main advantage of this method is that the shape of the particle can be arbitrary, and multiple scattering can be considered in the internal scattering processes. A dense-medium light-scattering theory based on the introduction of the static structure factor is used to calculate the phase function and asymmetry parameters for densely packed inclusions. Numerical results of the single scattering characteristics for a sphere containing multiple densely packed inclusions are given.

Theoretical studies on particle shape classification based on simultaneous small forward angle light scattering and aerodynamic sizing

Particle shape contributes to understanding the physical and chemical processes of the atmosphere and better ascer- taining the origins and chemical compositions of the particles. The particle shape can be classified by the aspect ratio. which can be estimated through the asymmetry factor measured with angularly resolved light scattering. An experimental method of obtaining the asymmetry factor based on simultaneous small forward angle light scattering and aerodynamic size measurements is described briefly. The near forward scattering intensity signals of three detectors in the azimuthal angles at 120° offset are calculated using the methods of T-matrix and discrete dipole approximation. Prolate spheroid particles with different aspect ratios are used as the shape models with the assumption that the symmetry axis is parallel to the flow axis and perpendicular to the incident light. The relations between the asymmetry factor and the optical size and aerodynamic size at various equivalent sizes, refractive indices, and mass densities are discussed in this paper. The numerically calculated results indicate that an elongated particle may be classified at diameter larger than 1.0 μm, and may not be distinguished from a sphere at diameter less than 0.5 μm. It is estimated that the lowest detected aspect ratio is around 1.5： I in consideration of the experimental errors.

Reversible Aggregation Kinetics of Poly(N-isopropylacrylamide-co-N-vinylpyrrolidone) in Aqueous Solutions Revealed by Elastic Light Scattering Spectroscopy

Poly（N-isopropylacrylamide-co-N-vinylpyrrolidone） [P（NIPAM-co-NVP）] copolymers with different content of N-vinylpyrrolidone （NVP） were synthesized, and reversible aggregation kinetics of the copolymers in aqueous solutions was investigated with elastic light scattering （ELS） spectra. The results indicated that the apparent activation energy of aggregation process during heating and dissociation process during cooling increased with the NVP content increasing. The phase transition temperature also increased as the content of NVP increased, suggesting that the hydrophilic nature of NVP strongly affected the phase behavior of the copolymer solutions. The higher the content of NVP, the higher the temperature required to break the balance between the hydrophilic and hydrophobie interaction. Besides, during heating and cooling process, the phase transition hysteresis of P（NIPAM-co-NVP） chains decreased when the hydrophilic comonomer increased.

Resonance Light Scattering Method for Determination of Amikacin with Potassium Ferrioxalate as a Probe

In a weak acid medium, potassium ferrioxalate（PF） can react with some aminoglycoside（AGs） antibiotics, such as amikacin（AMK）, kanamycin（KANA）, tobramycin（TOB） and gentamicin（GEN）, to form ion-association complexes. It results in the enhancement of resonance light scattering（RLS） in different degrees. The maximum scattering peaks are all located at 345 nm. Among them, the relative scattering intensity（AIRLs） of AMK system is much higher than that of KANA, TOB or GEN. Therefore the method is more propitious to the determination of trace amounts of AMK. The optimum reaction conditions, influencing factors, and the relationship between scattering intensity and concentration of antibiotics were investigated by means of the proposed method. The enhancement of RLS signals is directly proportional to the concentration of antibiotics in a certain range of concentration. A new resonance light scattering method for the determination of AMK and other aminoglycoside antibiotics with [Fe（C2O4）3]^3- as a probe is thus established based on it. The method exhibits high sensitivity and good selectivity. The detection limit（3σ） for AMK is 1.8 ng/mL. The method can be applied to the determination of AMK in clinical serum samples. The reaction mechanism and the reasons for RLS enhancement are discussed in this paper.

Dynamical Casimir effect in superradiant light scattering by Bose Einstein condensate in an optomechanical cavity

We investigate the effects of dynamical Casimir effect in superradiant light scattering by Bose-Einstein condensate in an optomechanical cavity. The system is studied using both classical and quantized mirror motions. The cavity frequency is harmonically modulated in time for both the cases. The main quantity of interest is the number of intracavity scattered photons. The system has been investigated under the weak and strong modulations. It has been observed that the amplitude of the scattered photons is more for the classical mirror motion than the quantized mirror motion. Also, initially, the amplitude of scattered photons is high for lower modulation amplitude than higher modulation amplitude. We also found that the behavior of the plots are similar under strong and weak modulations for the quantized mirror motion.