University of Kerala
  • Thiruvananthapuram, India
Recent publications
All landscapes, including estuarine islands, normally try to restore their geomorphic isostasy in all anthropogenic interventions on land dynamics. Munroe Island has been experiencing drastic environmental degradation, such as land subsidence, severe tidal/monsoon flooding, subsidence of build-ups and a drastic decay in agricultural productivity. This paper examines the role of anthropo-geomorphic interventions causing for the land degradation in Munroe Island through a multidisciplinary approach. Multidated, multiresolution satellite products and published maps, spanning a period of about six decades from 1960 to 2021, were used to understand the different geomorphic and geographical processes in the study area. Evaluation of the temporal bathymetric datasets, salinity measurements of the river and estuary, borehole data logs of the area and electrical resistivity surveys of the island were analyzed to find out the causative factors for the disturbances in the land neutrality, along with the tidal hydrodynamic changes in the region. The study shows about 14% of the total land area was vanished during the study period, and more than 25% of the area is under stress, leading to further land degradation. More than 500 households are forced to vacate their residence due to land subsidence/flooding. Lack of required freshwater and sediment supply from the Kallada river after the construction of the Thenmala reservoir in the Kallada river as well as the uncontrolled sand mining prevailed are the key factors for the environmental degradation of Munroe Island. The paper describes the role and colinkages of human-induced hydrogeomorphic interventions on a geomorphic system, in charge of the environmental degradation and land subsidence crisis of an estuarine island ecosystem and discusses the concerns related to the management strategies of such region.
Remarkable feats of the past often leave behind historical pointers leaving us mesmerised. One such episode is that of the establishment of a magnetic and meteorological observatory on the peak of the Agasthiyar mountain 6200 feet above the sea level on the western Ghats in the year 1855 by John Allan Broun under the princely state of Travancore. It had facilities far ahead of its times representing the commitment to scientific universalism by its patrons. Broun established the observatory on the Agasthiyar mountain peak and undertook a meticulous study overcoming daunting geographical constrains. Broun was awarded the Keith Medal from the Royal Society of Edinburgh for the period 1859–1861. He received the Royal Medal from the Royal Society of London in 1878. He passed away in 1879. Remnants of the magnetic observatory which earned Broun scientific acclaim remain undiscovered, clouded within the Agasthiyar mountains.
Lead-free multiferroic magnetoelectric mixed and core shell composites of BaTiO3 and NiFe2O4 were synthesised by a two-step process. The structural, morphological, electrical, magnetic and dielectric properties of the as prepared samples were investigated in detail. XRD—Rietveld refinement (using JANA 2006 program) confirms the co-existence of two phases in the composite. The dielectric, ferroelectric and ferromagnetic properties of the systems was studied. The enhanced remanent polarization of core shell composite compared to pure BaTiO3 is the direct evidence of formation of core shell structure. The decrease in saturation values of composites can be attributed to the presence of nonmagnetic BaTiO3. The magnetoelectric coupling studies on BaTiO3@NiFe2O4 core–shell system exhibits enhancement due to the well-defined interface between the two phases. The sensitivity of electric properties to the applied magnetic field enables the systems for possible applications in magnetoelectric sensors.
Radiation-induced lung injury (RILI) is one of the most prominent complications of thoracic radiotherapy for which effective therapy is still lacking. This study investigates the nutraceutical potential of the culinary spice Amomum subulatum in mitigating thoracic radiation-induced pneumonitis (RP) and pulmonary fibrosis (PF). Mouse models of RP and PF were established by whole thorax irradiation at a dose of 25 gray. C57BL/6 mice were administered with 250 mg per kg body weight of methanolic extract of A. subulatum dry fruits (MEAS) for four consecutive weeks and observed for changes in lung tissue antioxidant activities, oxidative stress parameters, and expression of antioxidant, inflammation, and fibrosis-related genes by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and real-time PCR analysis, and histology analysis. MEAS administration reduced radiation-induced oxidative stress by enhancing the expression of Nrf2 and its target genes. Irradiation increased gene expression of inflammatory mediators and lung histology further confirmed the characteristics of RP, which were reduced by MEAS treatment. Immunohistochemistry analysis revealed the potential of MEAS in reducing the radiation-induced elevation of cyclooxygenase 2 expression in the lungs. The late sequel of RILI was manifested as PF, characterized by the elevated expression of pro-fibrotic genes and increased collagen content. However, MEAS administration markedly reduced radiation-induced fibrotic changes in the lungs. These effects might be attributed to the synergistic effect of bioactive polyphenols in MEAS with antioxidant, anti-inflammatory, and anti-fibrotic efficacies. Taken together, this study demonstrates the potential of MEAS in mitigating RILI, suggesting the possible nutraceutical application of A. subulatum against radiation toxicities.
The electromagnetic interference (EMI) shielding market is one of the fast-growing sectors owing to the increasingly complicated electromagnetic environment. Recently, priority has been given to improvise the techniques to fine-tune and predict the shielding properties of structures without exhausting raw materials and reduce the expense as well as the time required for optimization. In this article, we demonstrate an effective and precise method to predict the EMI shielding effectiveness (SE) of materials via simulating the performance of composites having alternate layers of conducting and magnetic materials in a virtual waveguide measurement environment based on the finite element method (FEM). The EMI SE of multilayered heterogeneous arrangements (MHAs) is simulated in the K-band region using ANSYS High Frequency Structure Simulator (HFSS) software, which can be extended to all other bands as well. Various simulations carried out by changing the order of the conducting and magnetic layers and the number of layers revealed that the strategic arrangement of electromagnetic (EM) energy-trapping layers inside the impedance-matching layers in the MHAs significantly contributes toward the enhancement of absorption-dominated EMI shielding. Among the MHAs, the conducting-magnetic-conducting (CMC) systems exhibited the highest shielding effectiveness of above 50 dB. The MHAs are realized for testing using poly(vinylidene fluoride)-based composites of low-cost carbon black and barium hexaferrite, an easily accessible ferrite. Through this study, we propose the idea that materials with high production cost and cumbersome fabrication procedures are not necessary to realize highly efficient shielding materials.
The structural, vibrational, electronic, and nonlinear optical properties of 4-amino benzoic acid pyrazinoic acid were obtained using spectral methods and density functional theory calculation. The title compound was characterized by Fourier transform infrared, Fourier transform-Raman, UV-Vis spectral studies and single crystal x-ray diffraction technique. By using density functional theory (DFT) using B3LYP method with 6-31 G(d,p) basis sets. The molecular geometry and vibrational frequencies were calculated and compared with the experimental data. The intermolecular contact of title compound was studied by Hirshfeld surface analysis whereas an intra-molecular hydrogen bonding interaction was examined through reduced density gradient plot. Molecular electrostatic potential and Fukui functions were also performed. Wave functional study like electron localization functions were analyzed. Bader’s theory of atoms-in-molecule conjointly with natural bond orbital have been analyzed. The natural bond orbital (NBO) analysis enabled in comprehending the stability and charge delocalization in the title molecule. The first hyperpolarizability which is an important parameter for future studies of nonlinear optics (NLO) was calculated to check the potential of the molecule to be an NLO material.
Lithium-rich cathode materials have emerged as promising materials for high-energy density lithium-ion cells due to their high specific capacity and high working voltage. In the present work, a comparative study has been made on the thermal stability and electrochemical performance of the lithium-rich cathode material, Li1.5Ni0.25Mn0.75O2.5 (LNMO, synthesized by a co-precipitation method) with commercially available nickel-rich cathode material, LiNi0.8Mn0.1Co0.1O2 (NMC 811). Thermal runaway is a major safety concern hindering the large-scale application of lithium-ion cells in the booming electric vehicle market, and thus the thermal stability of electrode materials has become an important criteria for practical applications. The thermal stability of the cathode materials is investigated by thermogravimetric analysis (TGA). The LNMO cathode material showed better thermal stability in delithiated state than the NMC 811 cathode. A comparative study on the electrochemical performance of both LNMO and NMC 811 cathodes at a working voltage window of 2–4.8 V showed a higher initial discharge capacity (263 mAhg−1) for NMC 811 electrode than LNMO electrode (234 mAhg−1). However, the cycling and rate performance studies indicate excellent performance for LNMO cathode than NMC 811 at the higher working voltage.
Objectives: This study employs text mining and natural language processing approaches for analyzing and unearthing public discourse and sentiment towards the recent spiking Measles outbreaks reported across the globe. Study design: A detailed qualitative study was designed using text mining and natural language processing on the user-generated comments from Reddit, a social news aggregation and discussion website. Methods: A detailed analysis was conducted using topic modeling and sentiment analysis on Reddit comments (n=87203) posted between October 1 and December 15, 2022. Topic modeling was used to leverage major themes related to the Measles health emergency and public discourse; the sentiment analysis was performed to check how the general public responded to different aspects of the outbreak. Results: Our results revealed several intriguing and helpful themes, including parental concerns, anti-vaxxer discussions, and measles symptoms from the user-generated content. The results further confirm that even though there have been administrative interventions to promote vaccinations that affirm the parents' concerns to a greater extent, the anti-vaccination or vaccine hesitancy prevalent in the general public reduces the effect of such intercessions. Conclusions: A proactive analysis of public discourse and sentiments during health emergencies and disease outbreaks is vital. This study effectively explored public perceptions and sentiments to assist health policy researchers and stakeholders in making informed and data-driven decisions.}
As circadian regulator, melatonin is involved in many physiological processes including ionosmotic regulation in fishes. Na+/K+-ATPase (NKA), an ubiquitous Na+/K+ transporter in ionocyte epithelia that drives electrochemical Na+ gradients and systemic osmotic integration, is a target of stress in fish. However, it is not certain how melatonin regulates NKA functions in ionocyte epithelia and how it modulates the adaptive response such as stress and ease response in fish particularly in hypoxia condition. We, thus, examined the short-term in vivo action of melatonin on the dynamics of NKA regulation in branchial, renal and intestinal ionocytes of hypoxia-induced air-breathing fish (Anabas testudineus Bloch). Interestingly, we found a rise in plasma melatonin in fish when kept for 30 min of forced submergence in water and that indicates a role for melatonin in hypoxia tolerance. A fall in blood [Na+ , K+] occurred in these hypoxic fish which later showed a recovery after melatonin treatment. Similarly, melatonin favored the fall in NKA activity in branchial and renal epithelia of hypoxic fish, though it remarkably stimulated its activities in non-stressed fish. Likewise, melatonin that produced differential pattern of mRNA expression in nkaα1-subunit isoforms (nkaα1a, nkaα1b and nkaα1c) and melatonin receptor isoforms (mtnr1a, mtnr1bb, mtnr1bb x1x2 ) in the tested ionocyte epithelia, showed reversed expression in hypoxic fish. In addition, the rise in NKAα-protein abundance in branchial and renal epithelia of melatonin-treated hypoxic fish indicated a recovery action of melatonin. A higher NKAα-immunoreactivity was found in the immunohistochemical and immunofluorescent images of branchial ionocytes and renal proximal and distal ionocytes of hypoxic fish treated with melatonin. Furthermore, an activation of PKA and PKG-dependent phosphorylation was found in branchial epithelia of hypoxic fish. The generated integrative parabola model showed that melatonin has a maximum targeted action on NKA function in the renal epithelia, suggesting its lead role in the integration of ionosmotic balance during the recovery or ease response. Over all, the data indicate a multidimensional and preferential action of melatonin on NKA regulation in fish ionocytes that integrate the recovery action against hypoxia, thus pointing to a major role for melatonin in stress and ease response in this fish.
We presented the idea of condition spectrum for a multi-array of complex numbers generally referred to as complex tensors. The application of the condition spectrum of tensors in the stability analysis of multilinear systems emphasizes the significance of this concept. It is shown that the condition spectrum of a tensor and a tensor pair is a Ransford spectrum. Some significant properties of the condition spectrum involving topological and geometrical aspects are developed. We demonstrated how to utilize a condition spectrum to assess the stability of a system of multilinear equations. Some examples and numerical experiments are done to illustrate the results.
Ageing of engine oil is an important issue determining the engine life and performance. The present work attempts to delineate the ageing-induced changes in engine oil through the mode-mismatched dual-beam thermal lens (MMDBTL) technique and other conventional spectroscopic techniques. For the analyses, engine oil samples were collected after every 200 km of runtime. As the thermal diffusivity is related to the nonradiative deexcitation upon optical absorption, comprehensive radiative and nonradiative analyses were carried out. The Ultraviolet-Visible, Fourier transform infrared, and Nuclear magnetic resonance spectroscopic analyses point to the structural modification as a result of the breaking of the long-chain hydrocarbons into ketones, aldehydes, esters, and other compounds. This modifies the absorption pattern, which can also be understood from the nonlinear refractive index study using the Z-scan technique. The compositional variations associated with the degradation upon ageing, the length of the hydrocarbon chain, and the formation of newer molecules account for the enhancement of the thermal diffusivity revealed through the MMBDTL techniques. The complementary nature of the radiative and nonradiative emission is understood from the fluorescence study. Thus, the study reveals the possibility of thermal diffusivity measurement as an effective tool for the quality monitoring of engine oil.
The tropical forests on earth play a vital role in ensuring highest biological diversity and the Western Ghats represents as one of the great diversity centers of the world. One important part of microbial diversity is phylloplane fungi, which includes rusts, smuts, powdery mildews, black mildews, tar spots, etc. Phylloplane fungi (leaf infecting micro fungi) are ectophytic obligate biotrophs infecting a wide range of flowering plants and produce black colonies on the leaf surface. They are distributed in the tropical and subtropical regions of the world. Black mildews shows more abundance than other groups of fungi. These black colony-forming organisms belong to different taxonomic groups, viz. Meliolales, Asterinales, Schiffnerulales, Hyphomycetous fungi, etc. This chapter deals with the diversity, distribution and host range of phylloplane fungi with respect to black mildews in the Western Ghats.
Bioresources are the biologically generated materials that support life on the earth. They include plants, animals, microorganisms, and the total biogenic products. The purposeful use of these resources involves the preparation of food, the discovery of value-added bio-products, and the generation of energy. So these resources have a significant role in agriculture, pharmacological industries, and the production of bioactive molecules with pharmaceutical and industrial potential, thus, contributing to the nation’s overall economic development. Bioresources are generally diverse and abundant in nature. Due to this rich diversity, people depend on these resources to get enough goods and services to meet their needs. Microbial diversity is very vast and can have a wide range of applications in the agriculture, environment, and pharmaceutical industries. Legumes provide food security to millions of populations, and climate-smart agriculture can enhance sustainable utilization. Medicinal plants are storehouses of bioactive molecules with antimicrobial, anticancer, antidiabetic, and hepatoprotective potential. Validation of the ethnomedicinal properties of such plants can lead to the identification of many drug leads, which will be beneficial to mankind. The purposeful over-use of natural resources will lead to socio-economic and environmental issues. The conservation and sustainable consumption of biological resources are very critical for maintaining the balance of our ecosystem. There are many strategies to be followed for the prevention of overexploitation of these resources. A strong focus should be given to improving the resource efficiency of the available biomass to develop novel products with reduced costs. In this aspect, the multidisciplinary research studies on the utilization of different resources would be beneficial for the advancements in health systems and industrial areas through scientific and technological innovation.
Leafy greens are nutrient-packed leaves of herbs, shrubs, or trees, consumed along with tender petioles and shoots as vegetables and complete a balanced diet. They are high in dietary fiber, eaten raw or cooked, and appreciated for their bland to tangy taste. The leafy greens of herbaceous plants, more so in the recent past, are being marketed in the form of microgreens. The microgreens are miniature seedlings of herbs, very tender, crunchy, fresh, and fragrant. Moreover, they are highly nutritional compared to mature leafy greens. Microgreens contain a considerably higher concentration of vitamins and carotenoids than mature plants, but the type and quantity differ among the microgreens originating from the different plant types. The current chapter focuses on the different aspects that should be considered while growing microgreens, as well as the information about seeds that are suitable to be raised as microgreens. Also, there is an account of the growth media, light, temperature, nutrient requirements, and other methods that may be adopted to cultivate microgreens either at home or on small-scale commercial farms. Preliminary studies have irrevocably proved the nutritional and health benefits offered by microgreens, and so the recent findings in this area are updated for the interested readers. Microgreens have a short growth period, and there is every chance that they will be contaminated during harvest, storage, and transport. Therefore, awareness about the necessity of axenic conditions for microgreen cultivation is also provided. Many pre and postharvest practices may be adopted to obtain fresh and healthy produce. This would enable us to bring variety to our food palette. Thus, it is clearly evident that if proper care is taken, microgreens can become a future food choice. Hopefully, we will be able to witness the impending microgreen revolution.
The reef sediment samples were collected to study the distribution of plastics in the Vembar group (Upputhanni, Nallathanni, and Puluvinichalli Islands - Eight samples from each island). The maximum number of plastics was found at Upputhanni Island (a total of 154 particles). Upputhanni Island occupied nearly 43.5% of the total plastic count, followed by Nallathanni Island (31.8%) and Puluvinichalli Island (24.6%). The Puluvinichalli Islands had the highest percentage of white plastics (26.3%), followed by Upputhanni (23.8%), and Nallathanni (14.2%). Plastics with irregular and fiber-like shapes predominated in the reef sediments. The polypropylene found in the reef sediments of the islands that make up the Vembar group was the most abundant sort of plastic, followed by polyethylene (19.6 %), polystyrene (5.7 %), and nylon (32.3 %). The outcome of this study suggests that the reef environment was less contaminated by plastics and was at low risk.
The genus Amorphophallus Blume ex Decne. is a vast and widespread group of aroids belonging to Araceae which is taxonomically and botanically distinct due to the frequency of emergence of inflorescences and their relatively short active period of existence. Amorphophallus paeoniifolius var. campanulatus or the elephant foot yam is an important tuber crop due to its high productivity and popularity as a vegetable in various delicious cuisines and medicinal properties. Wild congenerics of the cultivated A. paeoniifolius known as A. paeoniifolius Nicolson var. paeoniifolius (Decne.) Sivad. possess powerful therapeutic action against piles and gastro-intestinal disorders. The wide visible morphological variation observed in wild A. paeoniifolius morphotypes (morphological variants) available in the Western Ghats especially in the vegetative as well as inflorescence characters led to the present investigation to analyze and appraise the inflorescence diversity in comparison with other aspects, among the wild relatives of Amorphophallus paeoniifolius . Variation in the surface pattern of petiole and spathe is the main difference found within the species. The shape of appendix, the colour and pattern of spathe, scale leaves (bract) subtending the spathe, the male zone, female zone, the pollen morphology as assessed by SEM and pollen fertility showed distinct variation within the species revealing six distinct morphotypes. The mitotic chromosome studies indicated structural variation which was reflected in the karyomorphology. The ISSR markers, inflorescence /floral markers and vegetative morphological descriptors also indicated clear distinction between the morphotypes in addition to the variation seen in pollen morphology
Among Indian states, Kerala always stands out with its unparalleled achievements in social sector development. However, the fisherfolk, which accounts for almost 3.5% of the total population of Kerala, still suffers the scourge of exclusion from their material deprivation and employment-related insecurities. To ensure their inclusivity, the state, over the past decades, has introduced several social security initiatives such as welfare schemes, subsidies, direct benefit transfers, etc. Despite these efforts, a commensurate improvement is not visible in their standard of living. In this context, an attempt has been made to analyse the nature and role of the state-led social security measures in ensuring inclusivity based on data collected from various government sources and selected fisherfolk households in the Thiruvananthapuram district of Kerala. The study assessed different aspects of welfare schemes like nature, level of awareness, and the number of beneficiaries. Among the rolled-out schemes, a paucity of promotional schemes is observed. Likewise, the fisherfolk has lesser awareness about these schemes, and resultantly their enrolment rates are also low. These findings mirror the failures in state action in permeating the targeted community, and it points to the need for more strategic intervention on the part of the government. Formulating more capacity-building initiatives that can offer sustainable social protection and reaching out to coastal communities through innovative awareness campaigns are some of the means by which the state can reiterate its commitment to the inclusive development of marine fisherfolk.
Self-healing ability of epoxy have been aroused as a strategy to improve the performance of epoxy-based structures, coatings and adhesives. Though there are several reports on the development of self-healing epoxy, the sustained and controlled healing of epoxy matrix is critical for achieving desired performance. Hence, scientists paid much attention to designing self-healing systems that would trigger and act upon certain stimuli. The stimuli should be non-destructing and available in the user environment. Both intrinsic and extrinsic self-healing in epoxy systems have been tailored to respond to the external environment. Earlier, single stimuli responsive self-healing epoxy systems were introduced as smart materials with superior performance. Later on, dual-to multiple stimuli-responsive self-healing epoxy systems were developed. Moreover, other epoxy systems have been developed to sense different combinations of stimuli such as light, temperature, pH, moisture, and restore the original functionalities. As a budding research area, practicing more advanced designs on multi-stimuli self-healing would benefit future material developments.
Document scanning devices are used for visual character recognition, followed by text analytics in the software. Often such character extraction is insecure, and any third party can manipulate the information. On the other hand, near-edge processing devices are restrained by limited resources and connectivity issues. The primary factors that lead to exploring independent hardware devices with natural language processing (NLP) capabilities are latency during cloud processing and computing costs. This paper introduces a hardware accelerator for information retrieval using memristive TF-IDF implementation. In this system, each sentence is represented using a memristive crossbar layer, with each column containing a single word. The number of matching scores for the TF and IDF values was implemented using operational amplifier-based comparator accumulator circuits. The circuit is designed with a 180nm CMOS process, Knowm Multi-Stable Switch memristor model, and WOx device parameters. We compared its performance with that of a standard benchmark dataset. Variability and device-to-device related issues were also taken into consideration in the analysis. This paper concludes with implementing TF-IDF score calculation for applications such as information retrieval and text summarization.
Garcinia gummi-gutta is valued for its dried fruit rind used as a souring agent in traditional cuisine and for the extraction of natural hydroxy citric acid (HCA) in the formulation of anti-obesity nutraceuticals. The species is widely distributed in Kerala State but is not yet an economically profitable crop in the region. Promising germplasm screening based on the fruit mass traits of 180 trees was performed leading to the selection of 35 candidates plus trees (CPTs) characterized by the fewest fruits to weigh 1 kg (i.e., the largest fruits) with two fruit bearing seasons. Fruit mass data of 35 CPTs showed significant (P < .001) variations and highest fresh fruit mass (1091.27 kg), and dry rind mass (48.18 kg) recorded in CPT 6 and is 40-fold higher mass than mean fruit mass (25.4 kg) of 180 trees. Multivariate analysis and web diagram-based ranking supported selection of CPT 6 as a promising candidate tree. In the tree improvement programs through nutraceutical enrichment, the superior germplasm selected (CPT 6) in the present study can use effectively.
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Vaidyanathan Thankamani
  • Department of Bio-Technology
Achuthsankar S Nair
  • Department of Computational Biology & Bioinformatics
Manoj Changat
  • Department of Futures Studies
Shiburaj Sugathan
  • Department of Botany
Antony Helen
  • Department of Biochemistry
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