3D Mueller-matrix diffusive tomography of polycrystalline blood films for cancer diagnosis

The decomposition of the Mueller matrix of blood films has been carried out using differential matrices with polarized and depolarized parts. The use of a coherent reference wave is applied and the algorithm of digital holographic reconstruction of the field of complex amplitudes is used. On this basis, the 3D Mueller-matrix diffuse tomography method-the reconstruction of distributions of fluctuations of linear and circular birefringence of depolarizing polycrystalline films of human blood is analytically justified and experimentally tested. The dynamics of the change in the magnitude of the statistical moments of the first-fourth order, which characterize layer-by-layer distributions of fluctuations in the phase anisotropy of the blood film, is examined and analyzed. The most sensitive parameters for prostate cancer are the statistical moments of the third and fourth orders, which characterize the asymmetry and kurtosis of fluctuations in the linear and circular birefringence of blood films. The excellent accuracy of differentiation obtained polycrystalline films of blood from healthy donors and patients with cancer patients was achieved

Stokes-correlometry analysis of biological tissues with polycrystalline structure

Utilizing Stokes-correlometry analysis a new diagnostic approach has been introduced for quantitative assessment of polarization images of histological sections of optically anisotropic biological tissues with different morphological structures and physiological conditions. The developed approach is based on the quantitative assessment of coordinate and phase distributions of the Stokes vector of scattered light. A combined use of statistic, correlation, and fractal analysis is used for resolving variations in optical anisotropy of biological samples. The proposed combined application of the statistical, correlation, and fractal-based evaluates of spatial distributions of `single-point' polarization azimuth, ellipticity, and `two-point' Stokes vector parameters of polarization images of biological tissues histological sections demonstrates a high accuracy (Ac ≥ 90%) in monitoring of optical anisotropy variations within biological tissues

Embossed topographic depolarisation maps of biological tissues with different morphological structures

Layered topographic maps of the depolarisation due to diffuse biological tissues are produced using a polarisation-holographic Mueller matrix method approach. Histological sections of myocardial tissue with a spatially structured optically anisotropic fibrillar network, and parenchymal liver tissue with a polycrystalline island structure are successfully mapped. The topography of the myocardium maps relates to the scattering multiplicity within the volume and the specific morphological structures of the biological crystallite networks. The overall depolarisation map is a convolution of the effects of these two factors. Parenchymal liver tissues behave broadly similarly, but the different biological structures present cause the degree of scattering multiplicity to increase more rapidly with increasing phase. Through statistical analysis, the dependences of the magnitudes of the first to fourth order statistical moments are determined. These moments characterise the changing distributions of the depolarisation values through the volume of biological tissues with different morphological structures. Parenchymal liver tissue depolarisation maps are characterised by larger mean and variance, and less skewness and kurtosis, compared to the distributions for the myocardium. This work demonstrates that a polarisation-holographic Mueller matrix method can be applied to the assessment of the 3D morphology of biological tissues, with applications in disease diagnosis

Complementary analysis of Mueller-matrix images of optically anisotropic highly scattering biological tissues

Background: Using optical techniques for tissue diagnostics (so-called ‘optical biopsy’) has been a subject of extensive research for many years. Various groups have been exploring different spectral and/or imaging modalities (e.g. diffuse reflectance spectroscopy, autofluorescence, Raman spectroscopy, optical coherence tomography (OCT), polarized light microscopy, etc.) for biomedical applications. In this paper, we report on using multi-wavelength imaging Mueller polarimetry combined with an appropriated image post-processing for the detection of tissue malignancy. Methods: We investigate a possibility of complementary analysis of Mueller matrix images obtained for turbid tissue-like scattering phantoms and excised human normal and cancerous colorectal tissue samples embedded in paraffin. Combined application of correlation, fractal and statistical analysis was employed to assess quantitatively the polarization-inhomogeneous scattered fields observed at the surface of tissue samples. Results: The combined analysis of the polarimetric images of paraffin-embedded tissue blocks has proved to be an efficient tool for the unambiguous detection of tissue malignant transformation. A fractal structure was clearly observed at spatial distributions of depolarization of light scattered in healthy tissues in a visible range of spectrum, while corresponding distributions for cancerous tissues did not show such dependence. We demonstrate that paraffin does not destroy a fractal structure of spatial distribution of depolarization. Thus, the loss of fractality in spatial distributions of depolarization for cancerous tissue is related to the structural changes in the tissue sample induced by cancer itself and, therefore, may serve as a marker of the disease. Conclusion: The obtained results emphasize that a combined use of statistical, correlation and fractal analysis for the Mueller-matrix image post-processing is an effective approach for an assessment of variations of optical properties in turbid tissue-like scattering media and biological tissues, with a high potential to be transferred to clinical practice for screening cancerous tissue samples

From Victim Diaspora to Transborder Citizenship? : Diaspora formation and transnational relations among Kurds in France and Sweden

Denna avhandling är en komparativ undersökning av pågående förändringsprocesser bland kurder i Marseillesregionen i Frankrike och Stockholmsregionen i Sverige. I fokus står skiftet från en endimensionell och offerrelaterad kurdisk diasporisk identitet mot en mer sammansatt och aktiv. Studien går bortom entydiga erfarenheter av smärta, trauma och offerkänsla i syfte att lyfta fram en rad andra diasporiska situationer och företeelser såsom institutionella och transnationella formationer, assabiyya nätverk, ”on air” och ”online” verksamheter, kulturella och litterära aktiviteter osv., som samtliga är centrala element när det gäller att upprätthålla ett gränsöverskridande medborgarskap bland diasporiska kurder i de bägge länderna. Studien vidhåller dessutom att kurder i både Sverige och Frankrike på olika sätt är utsatta för diskriminering och socialt utanförskap. Avhandlingen visar hur kurder i Frankrike och Sverige utvecklar olika diasporiska diskurser och handlingsmönster. Beroende på en relativt likartad social bakgrund och på den exkluderande politiska miljö som finns i Frankrike så upprätthåller kurderna i Marseillesområdet en påtagligt offerrelaterad diasporisk diskurs. Samtidigt är framväxten av ett gränsöverskridande medborgarskap här starkt begränsad. Eftersom kurderna i Sverige är dels jämförelsevis socialt och politiskt diversifierade och dels vistas i en mer gynnsam politisk miljö upprätthåller de inte bara en mer flexibel diasporisk diskurs än kurder i Marseillesområdet. De har också utvecklat ett mer långtgående gränsöverskridande medborgarskap.This study is a comparative exploration of an ongoing process of change from a mono-dimensional, victim-related Kurdish diasporic identity to a more modulated, dynamic and active form of it among Kurds in the Marseille region in France and the Stockholm region in Sweden. The study goes beyond the experience of pain and trauma and the sense of victimhood in order to depict a multitude of other diasporic situations and trajectories such as institutional and transnational arrangements, assabiyya networks, “on air” and cyberspace “online” involvements, cultural and literary activities, and so forth, which are necessary elements for the development of the practice of transborder citizenship among diasporan Kurds in the two countries. The study argues that the Kurds in France and Sweden have conceived different diasporic discourses and at the same time have chosen different modes of action. Due to their uniform social background and the exclusionary French political environment, the Kurds in the region of Marseille maintain a tangible victim diaspora discourse and limited practice of transborder citizenship. As the Kurds in Sweden are socially and politically diversified, and as they live in the more favorable Swedish political environment, they maintain not only a flexible diaspora discourse but also a more highly developed practice of transborder citizenship than the Kurds in the Marseille region