Anomalous diffraction by arbitrarily oriented ellipsoids: applications in ektacytometry

Streekstra, Geert J.; Hoekstra, Alfons G.; Heethaar, R.M.

doi:10.1364/ao.33.007288

Cited by 47 publications

(28 citation statements)

References 17 publications

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“…RBC deformability of patients estimated by the Ecktacytometer at day0 is a summation of the cellular deformability of both uninfected (uRBCs) and infected ( Pf RBCs) RBCs fractions, with a contribution to the overall values proportional to their respective size31. Since the vast majority of RBCs in malaria patients are uRBCs, the reduction in RBC deformability results mainly from changes in the uRBCs.…”

Section: Resultsmentioning

confidence: 99%

Reduced erythrocyte deformability associated with hypoargininemia during Plasmodiumfalciparum malaria

Rey

Buffet

Ciceron

et al. 2014

Sci Rep

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The mechanisms underlying reduced red blood cell (RBC) deformability during Plasmodium falciparum (Pf) malaria remain poorly understood. Here, we explore the possible involvement of the L-arginine and nitric oxide (NO) pathway on RBC deformability in Pf-infected patients and parasite cultures. RBC deformability was reduced during the acute attack (day0) and returned to normal values upon convalescence (day28). Day0 values correlated with plasma L-arginine levels (r = 0.69; p = 0.01) and weakly with parasitemia (r = −0.38; p = 0.006). In vitro, day0 patient's plasma incubated with ring-stage cultures at 41°C reduced RBC deformability, and this effect correlated strongly with plasma L-arginine levels (r = 0.89; p < 0.0001). Moreover, addition of exogenous L-arginine to the cultures increased deformability of both Pf-free and trophozoite-harboring RBCs. NO synthase activity, evidenced in Pf-infected RBCs, induced L-arginine-dependent NO production. These data show that hypoargininemia during P. falciparum malaria may altogether impair NO production and reduce RBC deformability, particularly at febrile temperature.

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Section: Resultsmentioning

confidence: 99%

Reduced erythrocyte deformability associated with hypoargininemia during Plasmodiumfalciparum malaria

Rey

Buffet

Ciceron

et al. 2014

Sci Rep

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“…Streekstra et al 12 showed that the scattering by an ellipsoid of dimensions a, b, and c along the x, y and z axes, respectively, positioned at angles θ x , θ y , and θ z to the incident light is equal to the scattering by an ellipsoid characterized by dimensions a', b' and c' along the x', y', and z', respectively ( Figure 1). The orientation dependent dimensions a', b' and c' were calculated as functions of length a (b=a), width c, and orientation angles θ x and θ z as described in 12 . The coordinate transformation was done such as z' would align with the direction of the incident beam Io (Figure 1).…”

Section: Discussionmentioning

confidence: 99%

“…Anomalous diffraction approximation of van de Hulst 13 was used to predict the absorption and scattering from oriented ellipsoidal erythrocytes. The high accuracy of anomalous diffraction for predicting erythrocyte angle dependent scattering has been previously shown 12 . These results can be imported in the numerical models as empirical orientation constants, thereby, reducing their complexity.…”

Section: Introductionmentioning

confidence: 88%

“…The differences in size, shape, and hemoglobin concentration may cause natural variability in the erythrocyte spectral signatures. Yet, the variability in the erythrocyte orientation relative to the incident light due to the non-spherical shape 8,12 has the strongest effect on the erythrocyte spectral signatures. This problem becomes cumbersome and takes considerable computational power and time when solved numerically.…”

Section: Introductionmentioning

confidence: 99%

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Multi-wavelength spectroscopy of oriented erythrocytes

Serebrennikova

García‐Rubio

Smith³

et al. 2010

SPIE Proceedings

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Accurate characterization of the optical properties of erythrocytes is essential for the applications in optical biomedicine, in particular, for diagnosis of blood related diseases. The observed optical properties strongly depend on the erythrocyte's size, hemoglobin composition and orientation relative to the incident light. We explored the effect of orientation on the absorption and scattering properties of erythrocytes suspended in saline using UV-visible spectroscopy and theoretical predictive modeling based on anomalous diffraction approximation. We demonstrate that the orientation of erythrocytes in dilute saline suspensions is not random and produces consistent spectral pattern. Numerical analysis showed that the multi-wavelength absorption and scattering properties of erythrocytes in dilute suspensions can be accurately described with two orientation populations. These orientation populations with respect to the incident light are face-on incidence and edge-on incidence. The variances of the orientation angles for each population are less than 15 degrees and the relative proportions of the two populations strongly depend on the number density of the erythrocytes in suspensions. Further, the identified orientation populations exhibit different sensitivities to the changes in the compositional and morphological properties of erythrocytes. The anomalous diffraction model based on these orientation populations predicts the absorption and scattering properties of erythrocytes with accuracy greater than 99%. Establishment of the optical properties of normal erythrocytes allows for detection of the disease induced changes in the erythrocyte spectral signatures.

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“…These expressions reproduce accurately the extinction efficiency factor for randomly oriented spheroids, although these need not be good at a particular orientation. Scattering by ellipsoids in the ADA has been studied, among others, by Lind andGreenberg (1966), Latimer (1980), Sid'ko (1988), Paramonov (1994), Paramonov et al (1986), Streekstra et al (1994) and Streekstra (1994). A general bridging technique has been developed by Zhao and Hu (2003) to calculate the extinction efficiency factors for particles with various shapes and sizes.…”

Section: Nonspherical Scatterersmentioning

confidence: 99%

Light scattering and absorption characteristics of optically soft particles

Sharma

Springer Praxis Books

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Scattering techniques have been used to infer optical properties of macroscopic particles in various scientific disciplines for many years. To be able to deduce this information about the scatterer it is necessary to have an underlying theory for the analysis of measurements. Unfortunately, the exact analytic solutions are unknown, except in some simplest and most idealized cases. For a number of shapes numerical procedures are a possibility. But in many applications even a numerical approach still proves to be impracticable or even impossible and one needs to resort to approximation methods.Many particles of interest in nature are such that their refractive index m (relative to the surrounding medium) is close to unity, i.e., |m − 1| 1. These are called soft scatterers. A number of approximations have been developed for predicting optical properties of such particles. The purpose of this article is to review the situation regarding soft particle scattering and absorption approximations and study their optical characteristics.Parameters often employed to describe the validity domains in light scattering approximations are the size parameter x = πd/λ and a parameter 2x|m − 1| which can be looked upon as a measure of interaction strength. Here λ is the wavelength of the incident radiation and d is the characteristic size of the scatterer (e.g., the diameter of a spherical particle). Two domains may be identified for the purpose of this article. (i) 2x|m − 1| ≤ 1 (small phase shifts) and (ii) arbitrary 2x|m − 1| (arbitrary phase shifts). Small phase shifts Rayleigh-Gans-Debye approximationIf we denote by E i = E 0 exp(ik i .r − iωt) as the incident electromagnetic field, the four scattering amplitudes S 1 , S 2 , S 3 and S 4 at a large distance r from the scatterer may be defined by the following relation

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Anomalous diffraction by arbitrarily oriented ellipsoids: applications in ektacytometry

Cited by 47 publications

References 17 publications

Reduced erythrocyte deformability associated with hypoargininemia during Plasmodiumfalciparum malaria

Reduced erythrocyte deformability associated with hypoargininemia during Plasmodiumfalciparum malaria

Multi-wavelength spectroscopy of oriented erythrocytes

Light scattering and absorption characteristics of optically soft particles

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