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.

Aggregation and aging of nanoparticle-protein complexes at interfaces studied by evanescent-light scattering microscopy

Plasma protein-induced aggregation of nanoparticles(NPs)is a crucial issue in many applications,such as drug delivery.Although great efforts have been made to inves-tigate the protein adsorption kinetics or protein-induced NPs coalescence in bulk solutions,limited evidence has been uncovered for interfacial circumstances.Diet,disease,medicine,or senility could thoroughly change interfacial physicochemical properties of the inner lining of blood vessels.Implants including stents and artificial heart valves also have varied and evolutionary interfaces.Hence,there is an urgent need to understand the mechanism behind the non-specific protein adsorption and NP-protein aggregation in such interfacial cases.Here,we use evanescent light scat-tering to observe polystyrene NPs‒fibrinogen aggregation at substrates with varying surface properties.A density-fluctuation correlation function is utilized to reveal the relaxation dynamics of the aggregates.Both time-resolved and spatial-correlated evi-dence shows that the aging process of such soft materials is out-of-equilibrium,where the dynamics faster and slower than exponential can coexist in one sin-gle relaxation process.Besides,corona formation,inner stress,and interconnection together determine the microstructure,local adhesion,and structural relaxation of the aggregates,which can further correspond to the protein-to-NP ratio as well as the surface chemistry of NPs and substrates.

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.

Evaluation of corneal backward light scattering in type 2 diabetes mellitus

AIM:To compare the corneal backward light scattering values in type 2 diabetes mellitus(DM)patients with those of age and sex-matched healthy controls.METHODS:The study included 30 patients(30 eyes)with type 2 DM and 30 control subjects(30 eyes).Duration of diabetes,most recent hemoglobin A1c levels,along with the status of diabetic retinopathy,and existing medical treatment of all subjects were recorded.All subjects underwent a complete ophthalmologic examination.In addition,backward light scattering(densitometry)was measured to assess changes in corneal transparency using tomography(Pentacam HR).RESULTS:The type 2 DM patients included 12 males and 18 females and control subjects included 16 males and 14 females.The age was 50.40±7.80y(range:40-68y)of the diabetic group and 49.30±9.50y(rang:40-73y)of control group.The diabetic group demonstrated significantly higher mean densitometry values of the anterior(6-10 mm)zone(P=0.047),the total anterior layer(P=0.036)and the total cornea(P=0.043)than control group.The corneal densitometry of the diabetic eyes demonstrated no significant correlation with hemoglobin A1c levels and DM duration.CONCLUSION:Diabetic group has higher densitometry in anterior corneal(6-10 mm)zone,total anterior cornea,and total cornea and with no correlation with hemoglobin A1c levels and DM duration.

Effect of sodium nitroprusside on the microrheological properties of red blood cells in different media

Red blood cell(RBC)aggregation as well as their deformation significantly affects blood microrheology.These processes depend on various factors,one of which is concentration of the nitric oxide,one of the main signaling molecule in the bloodstream.The purpose of this study was to investigate the effect of nitric oxide on the microrheological properties of red blood cells(RBCs)in RBC samples of various media after the addition of nitric oxide donor sodium nitroprusside in vitro.Microrheological properties were measured using laser aggregometer and ektacytometer based on diffuse light scattering and diffraction of laser light on a suspension of RBCs,respectively.The study found that heparin-stabilized blood showed increased RBC aggregation and deformation with sodium nitroprusside concentrations of 100,and 200M,while EDTA-stabilized blood showed slightly decreased aggregation and unchanged deformation.With washed RBCs in dextran solution,the addition of sodium nitroprusside(in the concentrations of 100,and 200M)resulted in decreased aggregation and increased deformation.These-ndings aid in our understanding of nitric oxide's effect on RBC microrheological properties.

面向工业化种植的光热管理农膜——机遇与挑战

As indispensable parts of greenhouses and plant factories,agricultural covering films play a prominent role in regulating microclimate environments.Polyethylene covering films directly transmit the full solar spectrum.However,this high level of sunlight transmission may be inappropriate or even harmful for crops with specific photothermal requirements.Modern greenhouses are integrated with agricultural covering materials,heating,ventilation,and air conditioning(HVAC)systems,and smart irrigation and communication technologies to maximize planting efficiency.This review provides insight into the photothermal requirements of crops and ways to meet these requirements,including new materials based on passive radiative cooling and light scattering,simulations to evaluate the energy consumption and environmental conditions in a greenhouse,and data mining to identify key biological growth factors and thereby improve new covering films.Finally,future challenges and directions for photothermalmanagement agricultural films are elaborated on to bridge the gap between lab-scale research and large-scale practical applications.

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.