Institutional Repository

Scholar@UOC is the primary academic repository of the University of Calicut.

This repository is aimed to collect, preserve and distribute the research output of the members of our University. This is an open access system hosted and managed by the University Library.

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Now showing 1 - 5 of 38

Recent Submissions

Spectral characteristics of blazars: A detailed study of Mkn 421 and S5 0716+714.
(Department of Physics, University of Calicut., 2025) Baheeja C; Ravikumar, C. D.
The broadband SED of blazars is often modeled by a broken power-law function, in- dicating that the underlying electron distribution follows a broken power-law shape. However, one of the long-standing problems has been that the observed difference in the spectral index could not be explained solely by the radiative loss interpre- tation of the broken power-law electron distribution. Additionally, high-resolution observations have revealed curvature in the X-ray spectra of high-energy-peaked blazars. In the first part of the thesis, we aim to thoroughly investigate the radia- tive loss interpretation of the broken power-law electron distribution by studying the blazar spectrum around the synchrotron peak. We conduct a detailed analysis of the characteristic photon energy of blazar Mkn 421, where the spectral index changes significantly. Our findings indicate the presence of a strong anti-correlation between the spectral indices before and after this characteristic photon energy. This result contradicts the interpretation based on simple radiative loss for the characteristic photon energy, and alternative scenarios are thus discussed. Further, we carried out a detailed analysis on the observed curvature in the broadband X-ray spectrum of blazar Mkn 421. The curvature in the blazar spectrum can provide insights into the particle dynamics within jets. Our study suggests that the curvature in the X-ray spectra are consistent with a scenario where particle acceleration is governed by Bohm-type diffusion, and the spectra beyond the synchrotron peak are modulated by the radiative loss process. The latter part of this thesis focuses on a long-term, multi-wavelength spec- tral study of another blazar S5 0716+714. All available observations in optical/UV, X-ray, and gamma-ray wavebands of the source by Swift-UVOT/XRT or Fermi- LAT from April 2005 to January 2023 were used, and the spectra in each energy band were explored using power-law/log-parabola functions. A detailed correlationxiv study between the best-fit parameters was performed, and our results suggest that the spectral changes observed during high flux states could be associated with the spectral energy distribution shifting towards the blue end. Furthermore, the broad- band SED during two distinct flux states can be successfully fitted by considering synchrotron, synchrotron self-Compton, and external Compton emission processes. The flux enhancement of the source is predominantly associated with an increase in the bulk Lorentz factor. Additionally, we find that the model curves corresponding to variations in the bulk Lorentz factor have the potential to explain the observed correlations between the spectral parameters. Our study thereby suggests that the spectral variations of blazar S5 0716+714 are primarily associated with changes in the bulk Lorentz factor of the jet.
Muslim women in bollywood Tracing the political and cultural transitions
(Government Victoria College Palakkad, 2025) Shani A.Mopila; Sreepriya R.
Cinema as a cultural text functions as the roadmap in understanding the socio-political complexities of any nation. Bollywood exists in India as a nexus of the deceptive power play operated by dominant political structures over the Muslim minority subjects. The work attempts to read the representation of Muslim women in Bollywood as evolved out of the complex historical re-appropriations, majoritarian discourses and cultural nationalism in India. The study delves into an extensive research on the evolution of the character formations and narrative constructions in the films through which the popular images of Muslim women are constituted among the Indian spectatorship. The study has incorporated the critical perspectives and theories of Stuart Hall, Harold Lasswell, Louis Althusser and others. Through the exegesis of the film texts, the study postulates that the political transitions in the 1990s and the injection of cultural nationalism and Islamophobia into cinema have resulted in the misrepresentation of Muslim women and their lived experiences. By the foregrounding of Islamic religion as an oppressive agent and patriarchy as the exclusive domain of Muslim men, Muslim female characters are projected as reductive tropes of victims, nationalists and neo-liberal feminists. The research also contends that Bollywood, by nullifying the multilayered systemic oppressions faced by Muslim women, contributes to their erasure from cultural imagination and thus aligns with the majoritarian power politics.
Taxonomy of millipede Diplopoda fauna in the sacred groves of northern Kerala
(Christ College , Inrinjalakuda, 2026) Aswathy, M.D.; Usha Bhagirathan; Sudhikumar A.V.
Millipedes (Class: Diplopoda) are crucial macroarthropods of the soil ecosystem, contributing significantly to decomposition and nutrient cycling. Despite their ecological importance and wide distribution—excluding only Antarctica—they remain one of the least studied groups in Indian biodiversity research. This study, focused on the sacred groves of north Kerala, represents a pioneering effort in documenting the diversity, biogeography, and seasonal activity of millipedes in the region. Through extensive field surveys conducted over three years and integrative taxonomic approaches, the study elevated the known species count in Kerala from 57 to 70, including the discovery of nine species new to science, along with several new state and regional distributional records. The study also reported, for the first time in India, a mermithid nematode parasitizing a millipede, revealing unexplored aspects of diplopod parasitology. Observations on seasonality showed peak millipede activity from June to November, corresponding to the monsoon and post-monsoon periods. The documentation of widely distributed as well as endemic species reinforces the biogeographic uniqueness of the Western Ghats, particularly Kerala’s sacred groves and high-altitude regions, as critical refugia for rare and endemic taxa. This study underscores the importance of faunal documentation as the foundation of biological conservation, particularly for poorly studied and culturally sensitive ecosystems. However, challenges such as seasonal limitations, insufficient ecological data, and cultural restrictions on access to sacred groves was faced during field surveys. These barriers, coupled with increasing anthropogenic pressures, highlight the urgent need to integrate millipede taxonomy with conservation planning. Overall, the findings provide a significant baseline for future research in systematics, ecology, behaviour, and conservation of millipedes in India. The study emphasizes the necessity of habitat preservation, restoration of lost vegetation, and policy-level recognition of soil invertebrates as vital components of biodiversity. By illuminating the overlooked diversity of millipedes, this study reinforces the Western Ghats’ status as a global biodiversity hotspot that demands sustained scientific and conservation attention.
Synthesis characterization and bioactivities of chemically and biologically generated nanoparticles with special emphasis on antiproliferative potential in MCF 7 breast cancer cell line
(Department of Biotechnology, University of Calicut, 2025) Suhana Koothradan; Elyas K.K.
This study aimed to develop novel nanoparticle-basedtreatment strategies for breast cancer. For that, we used both thechemical and biological synthesis approaches; The first approachcreated an effective drug delivery system using chemically synthesizedIron oxide Gold core-shell-nanoparticles (IONPs). A bacterialmacrolide-derived compound, Rapamycin, which has already provenanti-proliferative ability in breast cancer cells, is used here to check theefficiency of the chemically synthesized nanocarrier system. In thesecond approach, the cell-free supernatant of the soil bacterial isolateswas used to synthesize Gold nanoparticles with anti-proliferativeproperties in the human breast adenocarcinoma cell line, MCF-7. Wealso characterized the AuNPs and assessed their anti-oxidant, anti-fungal, and anti-bacterial properties.The results documented the first report on the successfuldelivery of Rapamycin using the Au-IONP delivery system thatsuccessfully delivered and enhanced the anti-cancer activity ofRapamycin. And also, the first-ever production of gold nanoparticlesfrom Enterobacter hormaechei soil isolates with exceptionalanticancer and anti-bacterial potentials. This research successfullyconstituted two different methodologies for the synthesis ofnanoparticles with comparable anti-proliferative effects in breastcancer cells.
Effect of heavy metals on physiology and anatomy of Artemisia Nilagirica Clarke pamp
(Sri Neelakanda Govt. Sanskrit College, 2026) Fathimath Zuhra P.; Hussain K.
Artemisia nilagirica (Clarke) Pamp., commonly known as Indian wormwood, is a tall aromatic perennial shrub belonging to the family Asteraceae and is widely recognized for its therapeutic properties. The present study investigates heavy metal-induced stress responses and tolerance mechanisms in 4. nilagirica following exposure to aluminium (80 pM), chromium (70 pM), copper (50 pM), iron (70 puM) and mercury (10 pM) under Hoagland nutrient conditions. Roots, stems and leaves were analysed to assess morphological, anatomical, biochemical and metabolic alterations associated with metal toxicity. Metal exposure resulted in significant reductions in root and shoot length and leaf arca compared to control plants. Plants treated with mercury exhibited increased stomatal density and wider stomatal apertures, indicating an adaptive response likely facilitating mercury phytovolatilization. Copper exposure induced the development of glandular and non-glandular trichomes on both leaf surfaces, suggesting a sequestration-based detoxification strategy. Anatomical analyses revealed increased cell wall thickness as a key tolerance mechanism for immobilizing toxic metal ions and preventing cytoplasmic damage. Structural abnormalities, including disrupted epidermal layers and altered xylem vessel diameter, were observed in plants exposed to chromium, copper, iron and mercury, whereas aluminium treatment caused minimal anatomical alterations, indicating comparatively lower toxicity at the tested concentration. Biochemical analyses demonstrated a significant decline in tolerance index across all metal treatments. Chlorophyll content decreased, while carotenoid levels increased, reflecting a protective response against photooxidative stress. Elevated levels of proteins, phenolics, proline, malondialdehyde, and enhanced activities of antioxidant enzymes such as catalase and superoxide dismutase confirmed the induction of oxidative stress and activation of antioxidant defence mechanisms. SEM and SEM-EDX analyses revealed ultrastructural changes and confirmed the localization and accumulation of metal ions within plant tissues, while ICP-OES analysis validated metal bioaccumulation. GC-MS profiling revealed substantial alterations in the composition of bioactive secondary metabolites under heavy metal stress, including the emergence of compounds potentially involved in metal detoxification, alongside a reduction in metabolites associated with medicinal efficacy. FTIR analysis further demonstrated metal-specific modifications in functional groups of proteins and polysaccharides, indicating significant metabolic perturbations. Cytotoxicity studies using Dalton’s lymphoma ascites (DLA) cells showed that metal contamination significantly influenced the anticancer activity of 4. nilagirica leaf extracts; although cytotoxicity increased with extract concentration, overall anticancer efficacy was attenuated due to metal-bioactive compound interactions. Collectively, this study elucidates the complex physiological, biochemical, and molecular responses of A. nilagirica to heavy metal stress, highlighting its adaptive tolerance mechanisms, potential role as a bioindicator of metal pollution, and the need for careful evaluation of metal contamination in medicinal and therapeutic applications.