Generation of J0 Bessel Beams with controlled spatial coherence features

An alternative method to generate J0 Bessel beams with controlled spatial partial coherence properties is introduced. Far field diffraction from a discrete number of source points on an annular region is calculated. The average for different diffracted fields produced at several rotation angles is numerically calculated and experimentally detected. Theoretical and experimental results show that for this particular case, J0 Bessel beam is a limit when the number of points tends towards infinity and the associated complex degree of coherence is also a function of the number of points.Comment: 6 pages, 5 figure

The Development of Premortal Diagnostic Test for a-Synucleinopathies in Cerebrospinal Fluid and Blood

Synucleinopathies represent a group of neurodegenerative disorders characterized by the accumulation of abnormal α-synuclein protein aggregates in the central nervous system. Accurate and early diagnosis is crucial for effective treatment and management. This thesis explores the potential of various biomarkers in synucleinopathies, shedding light on their diagnostic accuracy, and clinical relevance. The study involves the analysis of CSF and blood biomarkers from synucleinopathy patients and control groups. A range of biomarkers including neurofilament light (NfL), prion proteins (PrPC and shedPrP), ubiquitin C-terminal hydrolase L1 (UCH-L1), glial fibrillary acidic protein (GFAP), Tau proteins (t-Tau and pTau181) and αsynuclein was investigated using assays based on the ultra-sensitive SIMOA technology and evaluated in terms of diagnostic accuracy. Neurofilament light emerges as a promising marker, while prion proteins exhibit distinct patterns in synucleinopathies. Furthermore, the study explores the complexities within synucleinopathies, including the intricate interplay between biomarkers and clinical measures and the nuanced differentiations among subgroups. Key findings include significant regulation of PrPC and shedPrP in synucleinopathies in comparison to controls suggesting their potential as sensitive diagnostic tools. Additionally, investigating the stability of biomarkers under different conditions and exploring their role in disease mechanisms may offer new insights into the pathophysiology of synucleinopathies. Aggregated α-synuclein was also detected using a real-time quaking-induced conversion assay, called RTQuIC. According to the signal response of RT-QuIC, we could discriminate synucleinopathies from controls. In conclusion, this thesis contributes to the evolving field of synucleinopathy research by elucidating the potential of biomarkers and emphasizing the need for comprehensive investigations to fully harness their diagnostic and therapeutic capabilities.2025-01-1

Attenuation of leaky modes and filtering techniques in graded index multimode fibres

This work is an investigation of leaky ray (mode) attenuation in graded multimode fibres. In contrast to slab or rectangular dielectric waveguides, cylindrical fibres possess leaky modes which greatly modify their propagation properties. The power carried by such modes eventually diminishes to zero, thus adding no useful contribution to the signal transmission over fibre channels. Suitable filtering techniques are therefore proposed. [Continues.