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

Tuning of negative permittivity and x band microwave absorption in pva nanostructured carbon metacomposites
(Department of Nanoscience and Technology, University of Calicut, 2024) Swetha, P; Sindhu, S.
The rapid advancement of technology has given rise to an ever-increasing demand for materialswith unique properties that can meet the challenges of modern applications. Among thesematerials, metamaterials and metacomposites have emerged as revolutionary innovations withthe potential to transform various fields, including telecommunications, aerospace, anddefence. Metacomposites, on the other hand, combine the properties of metamaterials withthose of conventional composite materials. This fusion allows for the creation ofmultifunctional materials that offer superior mechanical strength, thermal stability, andelectromagnetic performance. Such composites are particularly valuable in applications suchas in aerospace engineering, where lightweight, strong, and EMI-resistant materials are crucial.In the present study, polymer metacomposites are fabricated with polyvinyl alcohol as thematrix and three different carbon nanostructures such as carbon black, MWCNT and graphiteis used as the conducting fillers. All fabricated sample shows negative permittivity and goodshielding efficiency in the X- band region. After that a ceramic metacomposites are alsofabricated with BaTiO3 is the dielectric matrix and TiN is the conducting filler and the negativepermittivity is obtained. Then to impart flexibility this ceramic metacomposite is added in thepolymer matrix and in order to get negative permittivity different carbon nanostructures addedand this four-component system have high shielding efficiency and suitable for electromagneticinterference shielding applications.
Synthesis characterization and catalytic evaluation of modified nanocrystalline zeolites
(PSMO College, University of Calicut, 2024) Farsana, O. P.; Prajitha Kumari
Nano dimensions unveil a canvas of limitless possibilities.Decreasing the size of zeolite crystals to nanometer dimensionsimproves their characteristics by boosting surface area andminimizing diffusion path length. Research is focused on preparingzeolites with dispersed metal ions, especially high-silica zeolites,which are applauded for their effectiveness as catalysts in variouschemical reactions. The development of hierarchical zeolites withsecondary pore structures has been notable over the last decade.Additionally, zeolites doped with extra framework cations are foundto exhibit excellent dielectric properties. This study investigates thefundamental aspects of metals in zeolites and hierarchical zeolitestructures, discussing their applications for catalyzing reactions. Thesynthesized zeolites undergo a thorough characterization by FTIR,XRD, FESEM, UV-Visible spectroscopy, surface area, and surfaceacidity measurement. Furthermore, a comprehensive investigationinto the sustainable catalytic reactions facilitated by these metal-modified zeolites, analyzing how metals in zeolites impact theselective acetylation of toluene under minimal experimentalconditions. The study showcases innovative strategies for enhancingthe catalytic activity through developing hierarchical porosity innanocrystalline ZSM-5 and beta. Adding PMMA during nucleationminimizes internal defective silanols and successfully createshierarchically porous ZSM-5 zeolite. However, the zeolite beta synthesized with PMMA addition features narrowly distributedmesopores and microporous structure. This study also evaluates theeffectiveness of hierarchical ZSM-5 and zeolite beta in the selectiveacetylation of2-MON.Improved homogeneity of mesoporefeatures and active site environments enhances selective catalyticbehavior, highlighting the significance of heteroporous structures inzeolite catalysis. The study delves into the dielectric characteristicsof cerium-doped zeolite beta employing broadband spectroscopicmethods. The introduction of cerium induces significant variationsin dielectric readings, leading to remarkably high dielectric constantscompared to unmodified zeolite beta. Insights gained fromimpedance and modulus analyses contribute to the progression ofzeolite-based charge storage device technologies.The studysuggests that the research could lead to improvements in fixingdefects in zeolites and in making specific organic compounds formedicines using zeolite catalysts. It also hints at potential uses forzeolites as dielectric materials. Understanding the dielectricproperties of zeolites provides crucial insights for researchers andengineers to design applications beyond catalysis.
Efficacy of dialectical behaviour therapy based on emotion regulation in non suicidal self injurious behaviour
(Prajyothi Nikethan College Pudukkad, University of Calicut, 2024) Juleemol George; Jaya, A.T
The alarming prevalence and gateway effect of Non-Suicidal Self-Injury (NSSI) underscorethe urgent need for targeted interventions. This study explores the efficacy of Dialectical BehaviourTherapy (DBT) in reducing NSSI behaviour among individuals who engage in self-injury as amaladaptive coping mechanism to manage overwhelming emotions. In the Indian context, particularlyin Kerala, where mental health resources are limited and NSSI behaviour is on the rise, this researchis crucial to inform culturally-sensitive interventions and address the growing concern of self-injuryamong young adults. By addressing the underlying emotion regulation deficits DBT aims to providemore adaptive coping strategy ultimately reducing the frequency and severity of NSSI behaviour. Thestudy aimed to explore the natur¢ and psychological correlates of NSSI among young adults andevaluate the efficacy of DBT in enhancing psychological well-being (PWB).There are two phases in study. Phase I of the study followed a descriptive and predictiveresearch approach which focused on the nature and characteristics of self-injurious behaviour in thelast year and assessed effects of CER strategies on PWB among young adults with and without SIB.Participants for Phase -1 of the study comprised of 691 young adults aged 19 to 30 years. Phase IIconsisted of 21 partjcipants from three outpatient clinics in south Kerala, India. A quasi-experimentalresearch des"i"‘gn of one-group pre-post-test with an extended group was employed in phase IIintervention study. Participants who fulfilled the criteria for NSSI and who had not received anypsychological intervention in the past were selected for the study. Individuals taking medication forany chronic physical or mental illness or having any significant medical or neurodevelopmentaldisorder were excluded from the study.After obtaining informed consent from the participants and awareness of the research, threemeasurement scales Functional Assessment of Self-Mutilation (Lloyd et al., 1997), Cognitive EmotionRegulation Questionnaire (CERQ), (Garnefski & Kraaij, 2001), Ryff’s Scale for Psychological WellBeing(SPWB) (Ryff et al., 2007) were administered to individuals in the group with clear instructions.In Phase II after preliminary assessments with all measures participants underwent 14-week NeacsiuAdult DBT based on emotion regulation skill training. Post-intervention assessment was done withDeliberate Self Harm Inventory- Clinical Change Version II, CERQ, and SPWB. After 6 months offollow-up, final assessments were done with all measures by blind assessors. The study receivedcthical clearance from the Human Ethical Committee at the University of Calicut. Clear guidelineswere set foi'rconfidentiality and handling immediate suicide risks. Dropout cases were offeredtreatment upon return.The normality of the data was assessed using the Kolmogorov-Smirnov test in Phase I andShapiro-Wilk test in second phase. In Phase I Chi-square test, Mann-Whitney U test, Correlationanalysis, Linear Regression and Binary Logistic Regression were used in data analysis. In Phase IlFriedman test with pairwise comparisons by Wilcoxon signed-rank tests applying a Bonferronicorrection was used. Research reveals 11.3% of participants engaged in self-injurious behaviour (SIB) with cuttingbeing the most prevalent method. Social negative reinforcement including avoiding unpleasant tasksand evading social situations were highlighted as a common motive for SIB alongside social positivereinforcement such as seeking attention or elieiting reactions from others. Negative cognitive processesSelf-Blame and Rumination negatively impact Psychological Well-Being and are associated withincreased self-injury. 14-week adult DBT based on Emotion Regulation is found efficacious inreducing Self-Injurious by increasing and reducing in adaptive and non-adaptive strategies of EmotionRegulation and enhancing PWB. The study emphasizes the need for integrated approaches addressingcognitive and emotional factors in young adults with Non-Suicidal Self-Injurious Behaviour, bridgingtherapeutic modalities with positive psychological aspects in clinical psychology.
Physiological and anatomical studies on coleus amboinicus lour Subjected to heavy metals stress
(Sri NeelakandaGovt. Sanskrit College, University of Calicut, 2024) Sudheeshna, P. K; Hussain K.
The present study investigated the heavy metal-induced stress and tolerancepotential of Coleus amboinicus Lour., a widely used medicinal herb belongs toLamiaceae family. It is a large fleshy succulent perennial herb with aromaticpubescence and inherent medicinal properties due to the presence of manyphytochemicals and is known by a bunch of vernacular names ranging from Indianborage to “Panikoorka” in Malayalam.The plant's structural and functionalalterations were assessed through analyses of roots, stems, and leaves exposed toheavy metal stress. Rooted propagules were treated with Al (500 μM), Cr (150 μM),Cu (80 μM), and Hg (10 μM) in Hoagland nutrient medium. The immediateresponse to metal exposure was observed in morphology and anatomy. The effectsof heavy metals on development, growth, and metabolism were evaluated using arange of parameters, including stem, root, and leaf morphometry. Tolerance andstomatal indices were calculated to assess heavy metal impacts. Additionally,biochemical analyses were performed to quantify and qualify changes in protein,phenolic, proline, chlorophyll, and carotenoid pigment content. To investigate theheavy metal-induced oxidative stress, the activities of antioxidant enzymes,including catalase and superoxide dismutase, and malondialdehyde (MDA)production were analyzed in plant parts. Additionally, scanning electron microscopy(SEM) was employed to confirm anatomical changes in plant organs. Furthermore,SEM-energy dispersive X-ray spectroscopy (SEM-EDX) was used to determine thedistribution and localization of heavy metal ions in the plant tissues. Thebioaccumulation pattern of C. amboinicus for heavy metals was assessed usingInductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). Given theplant's medicinal importance, Gas Chromatography-Mass Spectrometry (GC-MS)was employed to analyze the occurrence and distribution of bioactive secondarymetabolites.Morphological analysis revealed slight growth retardation in root lengthacross all metal treatments compared to the control, with no significant differences between metals. The tolerance index percentage showed significant reduction in allmetal treatments compared to the control, with negligible differences betweenmetals. The reduction in photosynthetic pigments like chlorophyll content alongwith increase in carotenoids provides the plant with protection from photo oxidativedamage.In C. amboinicus treated with Hg, there is an increased number of stomataand a wider stomatal opening; and also, the presence of lenticels. These traits aredirectly linked to the removal of volatile forms of Hg, which is an indicator oftoxicity sequestration. An interesting observation in the Cu treatment is the removalof oil globules from stem and leaf. SEM images give the clear evidences for theremoval of oil globules. The possible reason for the removal of oil globules may bedue to the reduction of a secondary metabolite named alpha-bergamotene after Cutreatment. It is a major component of essential oils in various plants and itcontributes to the aromatic profile and therapeutic properties of essential oils. Theenhanced cell wall thickness plays vital role in efficient sequestration of toxic levelsof Cu2+ in the cell wall, thereby preventing the entry of toxic ions to the cytoplasmand enhancing Cu stress tolerance in C. amboinicus. Anatomical examinationrevealed that plants treated with chromium, copper, and mercury exhibitedsignificant structural changes, including a broken epidermal layer and alterations invessel size and shape. In contrast, aluminium-treated plants showed minimalanatomical changes, likely due to aluminium's essential role as a micronutrient witha negligible stimulatory effect on plant growth. According to GCMS results, effectof heavy metals resulting in the absence of many secondary metabolites which isvital for the antibacterial property of C. amboinicus whereas occurrence of somenew bioactive components especially Tetradecanoic acid,12-methyl-methyl estershows same properties.
Theoretical studies on the molecular basis of free radical scavenging mechanism and photoprotective potential of avenanthramides
(Department of Chemistry, University of Calicut, 2024) Sumayya, P.C; Muraleedharan, K.
The research work presented in this thesis comprises a theoretical study of the structural, electronic, and antioxidant properties of the Avenanthramides derived from oats. Avenanthramides are open-chain compounds containing two aromatic rings of an anthranilic acid derivative and cinnamic acid derivative and both these rings are connected through an α,β-unsaturated amide linkage. For this purpose, eight Avenanthramides of interest are selected and the geometry-optimized structures of these compounds are utilized for all the reactivity investigations using density functional theory methods. The major aim of the work comprises the comparative investigation of the radical scavenging activity of the selected compound by its structural and electronic features. The potential ability of these compounds to quench different radicals was studied both by thermodynamic as well as kinetic aspects. For this purpose, the work explored several pathways within the mechanism proposed in the literature. The possibilities of various radical stabilization pathways are also studied using electronic parameters. Utilizing the thermodynamic cycle of the radical quenching process we expanded the ability of these compounds towards a pool of radical species. Moreover, the UV absorbance and UV filtering activity of the selected compounds were analyzed. The obtained UV filtering activity and radical quenching ability of these compounds especially caffeic acid-based compounds are found to exhibit excellent photoprotective ability.