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Characterization of Turbid Media Using Stokes and Mueller-Matrix Polarimetry

Thesis Info

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Author

Manzoor Ahmad

Program

PhD

Institute

Pakistan Institute of Engineering and Applied Sciences

City

Islamabad

Province

Pakistan

Country

Pakistan

Thesis Completing Year

2014

Thesis Completion Status

Completed

Subject

Mathemaics

Language

English

Link

http://prr.hec.gov.pk/jspui/handle/123456789/1117

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676725699004

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In this thesis we present the application of polarized light to characterize porcine liver and phantoms with matched bulk optical properties, correlate the depolarization of tissues with transport albedo and evaluate the severity of liver injury. We have used the Mueller matrix analysis and polar decomposition method for extraction of individual polarization properties in this thesis. We investigated the polarization properties of thick samples (1 cm) of porcine liver, intralipid phantoms and polystyrene micro-spheres phantoms with matched bulk optical properties. Significant depolarization differences between porcine liver and phantoms are observed. Contrary to previously reported results for transmission geometry, our results show the enhanced polarization preservation for porcine liver tissues as compared to fabricated phantoms, particularly in the backscattering detection geometry. Moreover, the intralipid phantoms, polarization behavior is well- approximated with liver tissue as compared to the polystyrene sphere phantoms. Polarized light imaging was employed to investigate the correlation between light depolarization and transport albedo for six different isotropic and anisotropic thick tissues in both transmission and backscattering mode. Total, linear and circular depolarization rates were observed to be dependent on the measured transport albedos, where depolarization increases with transport albedo for all type of tissues independent of detection geometries. Higher depolarization rates were observed for anisotropic tissues as compared to isotropic ones for comparable transport albedos, demonstrating the birefringence-caused depolarization in addition to scattering-caused depolarization. The ex vivo severity assessment of different liver injuries induced by carbon tetra chloride (CCl4) was probed by polarized light in the visible spectral range. Less injured liver samples show higher linear retardance as compared to normal liver tissue, while worse injuries correspond to almost no retardance. Fibrosis is the likely cause at less severe injuries results in higher observed linear retardance whereas more serious injuries destroy any kind of organization and hence yield no retardance. Furthermore, total- linear- and circular-depolarizations were observed to decrease with increased injuries. Most likely causes include change of transport albedo and relative refractive index of extracellular matrix.
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خواجہ عبدالحئی فاروقی

خواجہ عبدالحی فاروقی
افسوس ہے پچھلے دنوں لاہور میں خواجہ عبدالحی صاحب فاروقی داعیٔ اجل کو لبیک کہہ کر رہ گزاے عالمِ جاودانی ہوگئے۔مرحوم بلندپایہ عالم، مفسر اور اسلامیات کے فاضل تھے۔تعلیم کی تکمیل دارالعلوم دیوبند میں کی تھی۔عرصۂ دراز تک جامعہ ملیہ اسلامیہ دہلی میں شیخ التفسیر رہے۔تقسیم کے بعد پاکستان منتقل ہوکر اسلامیہ کالج لاہور میں صدر شعبۂ علوم اسلامیہ ہوگئے تھے۔طبعاً کم سخن اور مرنج و مرنجان مگر بڑے خلیق و ملنسار تھے،اﷲ تعالیٰ رحمت وبخشش کی نعمتوں سے نوازے۔ [مارچ ۱۹۶۵ء]

مکی دور نبوت اور مسلم اقلیت کافقہ السیرۃ کی روشنی میں سماجی مطالعہ

The life of Holy Prophet (peace be upon him) is described as role model in Holy Quran for all the Muslims and known as Uswa.e. Hasna. So, the importance of the life history of the Holy Prophet (peace be upon him) in every period before prophet hood and as a prophet cannot be denied in any walk of life. But the makki period of the Prophet’s life has not enlightened in such a way as it has importance. Many aspects of makki period has been discussed in history and seerah writing but along with this a lot of aspects has been not given due importance in contemporary seerah writing. The basic sources of hadith o seerah provides lots of material on this aspect. In the makki period, Muslims were in minority and they had to face a lot of religious, social, economic and political issues in their lives. Now a days, in modern world majority of Muslims lives in western and non. Muslim societies and have to spend their lives as minority in that socities. In a state of minority, they have to face a lot of religious, social and economical issues in their lives. These problems can be solved in the light of seerah especially from the teachings of makki period, it can provide a lot of religious solutions in contemporary societies in a better way. This article will throw light on teachings of makki period and discuss the solutions of Muslim’s problems as minority in the light of fiqh. Ul. Seerah.

Reconstruction of Qualitative Gene Regulatory Networks

Genes provide instructions for the synthesis of functional products, such as, proteins. Gene expression develops the functional products using the instructions encoded in the genes. Gene regulation controls the process of gene expression in a way that it can regulate the increase or decrease of the gene expression resulting in the synthesis of specific functional products. It also controls when or when not to express a particular gene to produce a particular protein. Collection of regulatory elements, such as, genes and their interconnections showing the gene expression levels, are visualized as a Gene Regulatory Network (GRN). GRNs act as a tool for understanding the causation relationships between the genes and proteins representing complex cellular functionalities. Computational biology has laid its main focus nowadays on the reverse engineering or reconstruction of GRNs from gene expression data to decode the complex mechanism of the cellular functionalities. These efforts have resulted in improved and more precise diagnostics and therapeutics. Microarray technology of analyzing gene expressions calculates expression of thousands of genes simultaneously under different conditions, like, control or disease conditions. It helps in identifying over-expressed genes likely to be associated with the disease. Multiple approaches to reconstruct GRNs from gene expression data, apply various techniques, such as, distance measures, correlations, mutual information algorithms, dynamic and quantitative probabilities. These approaches result in identifying symmetric and diagonal gene pair interactions. Symmetric gene pair interactions cannot be modeled as direct activation and inhibition interactions. Moreover, diagonal nature shows that a gene cannot self-regulates itself, which is also contradictory with the true nature of gene pair regulatory interactions. Compromising the true asymmetric and non-diagonal nature of the actual gene pair regulatory interactions, can lead to incomplete and inferior predictions. To our knowledge, no such complete model exists to generate GRN representing all possible network motifs between gene pairs, such as, activation, inhibition and self-regulations. The proposed approach, named as, Multivariate Covariance Network (MCNet), aims at reconstructing GRN applies multivariate co-variance analysis and Principal Component Analysis (PCA) to identify asymmetric and non-diagonal gene interactions. The GRN developed using the MCNet approach holds all the possible network motifs, representing all kinds of gene-pair regulatory interactions (i.e., positive and negative feedback loops as well as self-loops). The asymmetry is achieved by computing the distance measure of the genes with respect to the eigen values of the related genes showing variable behaviors under different conditions. PCA in the MCNet approach selects gene-pair interactions showing maximum variances in gene regulatory expressions. Asymmetric gene regulatory interactions help in identifying the controlling regulatory agents, thus, lowering the false positive rate of interacting genes by minimizing the connections between previously unlinked network components. The performance of the proposed approach, MCNet, has been evaluated using a real data set as well as three synthetic and gold standard data sets. The MCNet approach predicts the regulatory vi interactions with higher precision and accuracy as compared to some currently state-of-the-art approaches. The results of the MCNet approach using the real time-series RTX therapy data set identified self-regulatory interactions of the differentially expressed (DE) genes with 80.6% accuracy. The MCNet approach predicted the gene regulatory interactions of the time-series synthetic Arabidopsis Thaliana circadian clock data set with 90.3% accuracy. The self-regulatory interactions identified in the RTX therapy and synthetic Arabidopsis Thaliana data sets are further verified from the literature because gold standards are not available for these data sets. Gold standard DREAM-3 and DREAM-8 in silico data sets, are also used to evaluate the performance of the proposed approach, while comparing with some existing approaches. The DREAM-3 in silico E-coli gold standard data set does not contain any self-regulations, while the DREAM-8 in silico phosphoproteins gold standard data set hold self-regulations. The results demonstrate the enhanced performance of the MCNet approach for predicting self-regulations only in the DREAM-8 in silico phosphoproteins data set with 75.8% accuracy. The MCNet approach for reconstructing GRN identifies direct activation and inhibition interactions as well as self-regulatory interactions from microarray gene expression data sets. The generated GRN can constitute positive and negative feedback loops as well as self-loops to demonstrate true nature of the gene-pair regulatory interactions. In future, it is aimed to enhance the functionality of the MCNet approach by modeling the dynamics of the GRNs, such as, oscillations and bifurcations towards steady state