PHD SEMINARS INVITATION

SPEAKER 1: Mr. John Githaiga, PhD Student Dept. of Physics, UoN 

    - Presentation: 11:00 am - 11:30 am

    - Questions    : 11:30 am - 12:00 pm

 

TITLE: Chemometrics Enabled Raman Spectrometric Qualitative Determination and Assessment of Biochemical Alterations during Early Prostate Cancer Proliferation in Model Tissue 

 

SUPERVISORS: H. K. ANGEYO, 

 

ABSTRACT:

 

The use of Raman spectroscopy combined with multivariate chemometrics for disease diagnosis has attracted great attention from researchers in recent years. This is because it is a non-invasive and non-destructive detection approach with enhanced sensitivity. However, a major challenge when analyzing spectra from biological samples has been the detection of subtle biochemical alterations buried in background and fluorescence noise. This work reports a qualitative chemometrics–assisted investigation of subtle biochemical alterations associated with prostate malignancy in model biological tissue (metastatic androgen insensitive (PC3) and immortalized normal (PNT1a) prostate cell lines), in 500-1800 cm-1 region, based on 785 nm laser excitation. Raman spectra were acquired from PC3 and PNT1a cells at various stages of growth and their biochemical alterations determined from difference spectra between the two cell lines (for prominent alterations) and Principal Component Analysis (PCA) (for subtle alterations). The Raman difference spectra were computed by subtracting the normalized mean spectral intensities of PNT1a cells from the normalized mean spectral intensities of PC3 cells. These difference spectra revealed prominent biochemical alterations associated with the malignant PC3 cells at the 566 ± 0.70 cm-1, 630 cm-1, 1370 ± 0.86 cm-1 and 1618 ± 1.73 cm-1 bands. The band intensity ratios at 566 ± 0.70 cm-1 and 630 cm-1 suggested that prostate malignancy can be associated with an increase in relative amounts of nucleic acids and lipids respectively, whereas those at 1370 ± 0.86 cm-1 and 1618 ± 1.73 cm-1 suggested that prostate malignancy can be associated with a decrease in relative amounts of saccharides and tryptophan respectively. In the analysis using PCA, intermediate-order and high-order principal components (PCs) were used to extract the subtle biochemical fingerprints associated with the cell lines. This revealed subtle biochemical differences at 1076 cm-1, (1232, 1234 cm-1), (1276, 1278 cm-1), (1330, 1333 cm-1), (1434, 1442 cm-1) and (1471, 1479 cm-1). The band intensity ratios at 1076 cm-1 and 1232 cm-1 suggested that prostate malignancy can be associated with an increase in subtle amounts of nucleic acids and Amide III components respectively. The method reported here has demonstrated that intermediate-order and high-order principal components (PCs) are potentially useful in extracting subtle biochemical alterations from Raman spectra of normal and malignant cell lines. The identified subtle bands could play an important role in quantitative monitoring of early biomarker alterations associated with prostate cancer proliferation.  

 

SPEAKER 2- ( PHD PROPOSAL PRESENTATION): Mr. Fredrick Mwange Mulei, PhD Student Dept. of Physics, UoN 

    - Presentation: 12:00 pm - 12:30 pm

    - Questions    : 12:30 pm - 1:00 pm

 

TITLE: Design Of Self-Cleaning Nanostructured Protective Glass for Photovoltaic Solar Panel 

 

SUPERVISORS: R. J. Musembi, A. A. Ogacho & Ulrich Wilhelm, Karlsruhe Institute of Technology, Germany

 

ABSTRACT:

 

 

Photovoltaics are the cornerstone of future sustainable energy supply. Over the years,

photovoltaics have shown great potential as an alternative source of energy to complement

the fossil fuel for energy generation. A number of photovoltaic (PV) technologies have been

developed over the last few decades. The photovoltaic technologies which have so far been

commercialised are those from silicon and thin films technologies. In the field application,

The performance of photovoltaic devices are affected by a number of factors such as the

incidence of solar irradiance, dust and soiling, shading, PV module temperature, inclination,

orientation and latitude. Out of these factors affecting the performance of the solar module

when in operation, some are easy to mitigate and minimize power losses, while other factor

are labour intensive and requires time for human intervention like effect of dust and soiling

on the module. Dust and soiling causes light scattering and reflection that is greater than or

equal to incident light on the active area of the solar cell consequently, reducing its power

conversion efficiency. In order to reduce human intervention through cleaning of the panels, this study proposes to develop a novel anti-soiling coating. Two types of anti-soiling techniques will be investigated based on previous studies done elsewhere which includes hydrophobic and hydrophilic. 

 

 

In this work, fluorinated ethylene propylene (FEP), and modified SiO 2 and ZnO are proposed to

be used as anti-soiling material because FEP has properties such as excellent optical

properties, can withstand weathering, and is resistant to ultraviolet degradation. To test their

efficacy, a comparative study on their self-cleaning effectiveness will be performed using

established reference soiling standards under indoor and real world conditions outdoor

operating conditions using AFM and SEM equipment. It is expected that the results of this

study will bridge the knowledge gap on solar PV self-cleaning techniques. This will enhance

possibility of facile outdoor application of solar PV self-cleaning coatings.

 

 

ALL ARE WELCOME AND PLEASE KEEP TIME!

 

 

SEMINARS COORDINATOR, DEPT. OF PHYSICS