Mapana Journal of Sciences

Editorial

Manoj Balachandran — Mon, 05 May 2025 00:00:00 +0000

The Rise of Candida auris: A Review of a Globally Emerging Multidrug-Resistant Pathogen

Vishal Bhoir, Bela Nabar — Sat, 05 Apr 2025 00:00:00 +0000

The emerging multidrug-resistant fungal pathogen Candida auris poses a serious global public health threat. Since its identification in 2009, C. auris has rapidly spread worldwide and can cause difficult-to-treat nosocomial outbreaks and invasive infections with high mortality. C. auris exhibits frequent resistance to azoles, echinocandins, and polyenes, creating challenges for its clinical management. Its ability to persistently colonise patients and contaminate hospital environments also facilitates easy transmission. This review summarises current knowledge on C. Auris global epidemiology, mechanisms of antifungal resistance, limitations of current treatments, and emerging novel therapies under investigation. Ongoing research priorities include improving diagnostics, elucidating pathogenesis, developing new therapies, and optimising infection control. Mitigating the public health risks of this formidable fungal pathogen remains an urgent goal requiring focused efforts across multiple domains.

Silent Invaders: A Review of Microplastic Accumulation and Its Impacts on Marine Commercial Invertebrates

Devika P Uday, Chitra Som R S, Balamurali R S — Sat, 05 Apr 2025 00:00:00 +0000

A new class of contaminants known as microplastics (MPs) has emerged in our environment due to the increased production and consumption of plastic products. Among the various sources of microplastics are larger plastic wastes, synthetic fabrics, and industrial goods. Microplastics, from surface waters to deep-sea sediments, are everywhere in the marine food web. Marine environments, especially marine invertebrates, which provide essential seafood, are being threatened by microplastic pollution. Marine invertebrates are particularly vulnerable to the ingestion, bioaccumulation, and related toxicological consequences of microplastics despite their crucial roles in trophic dynamics and biogeochemical cycles. This review article investigates microplastics' prevalence, sources, and effects on marine invertebrates worldwide. Results from multiple studies are compiled in this review to illustrate the extent of microplastic pollution in different marine environments and the biological consequences for invertebrate species. Important discoveries reveal that various marine invertebrates consume microplastics, negatively impacting their physiology, reproduction rates, and survival. The review addresses the trophic transfer of microplastics within food webs, the interaction with co-contaminants, and the potential for long-term ecological consequences. As part of the review, gaps in current research are identified and future directions are suggested for investigating the effects of microplastic pollution on marine ecosystems.

Luminous Blue Variables: A Step Towards Exploring a Critical Phase in Massive Star Evolution

Sat, 12 Apr 2025 00:00:00 +0000

Luminous Blue Variables (LBVs) are a rare class of early type, bright variable stars of late O to A spectral types that
represent one of the most enigmatic phases in the evolution of massive stars. Optical spectra of LBVs display prominent
emission lines of HI, HeI, FeII, and [FeII], often showing P Cygni-type profiles indicating mass loss. Traditionally, LBVs
have been viewed as a transitional phase between massive O-type and Wolf-Rayet stars, marked by significant mass
loss, 10 to 100 times compared to normal supergiant stars having similar luminosity, through episodes of eruptions and strong winds. However, these enigmatic objects still remain mysterious but important to better understand the
life cycle of massive stars, motivating further investigations to unravel their true nature. In this article, we provide an introduction to the various observable properties of LBVs and explore both traditional and alternate models of their
origin. The article is written to motivate both young readers and scholars of the astronomy community by highlighting the importance of exploring these rare but exotic stars, the LBVs

Palmitic acid-induced endoplasmic reticulum stress links metabolic stress to senescence and regulates cell fate via PERK signalling in colon cancer cells

Sat, 05 Apr 2025 00:00:00 +0000

Palmitic acid promotes cancer progression and induces endoplasmic reticulum stress, which is associated with a misfolded/unfolded protein response. The study aims to explore the impact of metabolic-stress induced by palmitic acid on cell fate decisions in colon cancer cell HCT15, with a specific focus on PERK signalling that connects metabolic-stress to senescence. Palmitic acid-induced oxidative stress is evidenced by increased ROS production, elevated MDA levels, and alterations in antioxidant activities. Bioinformatics analysis of GEO datasets on senescence in HCT15 cells revealed a PERK-mediated pathway, supporting a link between palmitic acid-induced metabolic stress and senescence. This study emphasises the critical role of palmitic acid-induced ER stress in connecting metabolic stress to senescence in colon cancer cells and the involvement of PERK signalling as a key mediator in this process. These insights provide a deeper understanding of how metabolic stress contributes to senescence, potentially revealing new therapeutic targets for managing colon cancer progression.

Photocatalytic and antibacterial properties of carbonaceous materials coupled NiO nanocomposites

Sun, 06 Apr 2025 00:00:00 +0000

The photocatalytic and antibacterial characteristics of pure NiO (NO), GO, and rGO integrated NiO (GNO and rNO) nanoparticles have been compared in this work. Through the process of chemical precipitation, NO and GNO NPs were created. Through the use of Centella asiatica leaf extract to reduce graphene oxide to rGO, rNO NC was produced utilizing one-pot green synthesis technique. The cubic crystal structure of all the samples shows a clear preferential growth along the (2 0 0) direction. Graphene oxide and reduced graphene oxide blending have a detrimental effect on the crystalline quality of NO. Reduced band gaps for the GNO and rNO samples were observed resulting from charge delocalization from electronic interaction between NiOand GO/rGO. The degradation efficiencies of NO, GNO and rNO catalysts were 78, 83 and and 92 %,respectively against rhodamine B after 100 min of light irradiation. The antibacterial properties of NO, GNO, and rNO NPs are differentiated by their size and ability to generate reactive oxygen species. Due to decreased crystallite size more ROS are generated for rNO and hence enhanced antibacterial potency has been realized.

Fluorescence Quenching Analysis of 6MNPM Molecule by Steady State Method

Srinath, Dayanand Lalsangi, Vijayalalaxmi Mallayya, S M Hanagodimath — Sat, 05 Apr 2025 00:00:00 +0000

The current work uses aniline as a quencher in a variety of solvents to investigate the room-temperature fluorescence quenching of a physiologically active fluorescent probe, namely “6-Methoxy-4-(4-nitro-phenoxy methyl)-chromene-2-one (6MNPM) coumarin molecule”. To understand its behaviour in various media, several solvents with different dielectric constants and refractive indices have been used. Spectroscopy techniques and time-correlated single photon counting were used to describe the absorption spectra, emission spectra, and lifespan value of a molecule. From fluorescence quenching analysis, we find that the S-V curve shows a linear dependence in given solvents with various dielectric values. It is shown that quenching responses are dynamic, many forms of quenching have been identified, and the relevant parameters have been assessed.

Effect of Synthetic and Natural Chelating Agent on Yttrium Iron Garnet (YIG) Nanocrystalline Powder via Sol Gel Method

M. Asisi Janifer, S. Anand, M. Muralidharan, M. Senthuuran, S. Pauline — Sat, 05 Apr 2025 00:00:00 +0000

The influence of synthetic and natural chelating agents on the structure, morphology, and magnetic properties of pure Yttrium Iron Garnet (Y₃Fe₅O₁₂) is examined. YIG samples are manufactured utilizing the synthetic chelating agent citric acid and the natural chelating agent lemon extract at varying temperatures. The generated samples are examined by X-ray Diffraction analysis (XRD). The X-ray Diffraction Pattern (XRD) revealed the garnet phase of nano ferrites at elevated temperatures. The morphological characteristics and elemental composition of the YIG samples are examined using High-Resolution Scanning Electron Microscopy (HRSEM) and Energy-dispersive X-ray Spectroscopy (EDAX), respectively. Metal oxide vibrations (M-O) and active Raman modes are analysed using Fourier Transform Infrared spectroscopy (FTIR) and Raman spectroscopy. The room-temperature magnetic characteristics of YIG samples are examined using a Vibrating Sample Magnetometer (VSM). The dielectric constant and dielectric loss of the nanomaterial are examined across multiple frequencies at varied temperatures.

Nonlinearities and Dielectric constant of Ge-Se Chalcogenide Glasses

Deepak Sharma — Sat, 05 Apr 2025 00:00:00 +0000

We recorded a transmission spectrum of Ge-Se glasses in the UV-visible range, revealing 80-90% transmission of light at room temperature. The percentage of light absorbed by these glasses is only 15%. The applicability of these glasses for the fabrication of single-mode optical fibre is being pursued by their high transmission and nearly nonexistent normal dispersion, while a small anomalous dispersion drop in the transmission is noticed at 720 nm in the UV-visible region. Drop in transmission at higher wavelength is explained in terms of absorption/photodarkening effect. Analysis of prepared glasses reveals direct band-gap material; thus, these materials can be used directly in fibre laser preparation. The refractive index obtained from spectra is modelled by Cauchy expression, and it is valid up to 700nm; beyond 700nm, wavelength increase in refractive index is modelled by poly4. Dielectric characteristics are examined and assessed. Ge-Se glasses have a decreasing dielectric constant as the band gap widens, indicating a decreasing trend in dielectric constant with increasing frequency.

A Theoretical Study of Coumarin Derivatives: Exploring DSSC, NLO Properties and Pharmacokinetics

Sat, 05 Apr 2025 00:00:00 +0000

This study presents a comprehensive theoretical analysis of the coumarin derivatives 1-(4-Methoxy-phenoxymethyl)-benzo[f]chromen-3-one (4MPBCO) and 6-Methoxy-4-(4-methoxy-phenoxymethyl)-chromen-2-one (6M4MPC) using density functional theory (DFT). The various molecular properties of these molecules are explored through the examination of geometrical parameters, frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) maps and natural bonding orbitals (NBO). The HOMO-LUMO energies were calculated to assess the suitability of these molecules for dye-sensitized solar cell (DSSC) applications. In addition, the non-linear optical (NLO) parameters were evaluated to determine their potential for NLO applications. Furthermore, the physicochemical and ADMET properties were computed to examine the molecule's suitability for pharmacokinetic applications.

Degree-Eccentricity Matrix of Graphs and Some Properties

Akhil B., Manju V. N., Roy John — Sat, 05 Apr 2025 00:00:00 +0000

This paper presents a new matrix for a given graph called the Degree-Eccentricity (DE) matrix, which consists of the degree and eccentricity of a vertex. Properties such as irreducibility and primitivity of this matrix are discussed. Further we obtain the spectrum and energy of DE matrices associated with various classes of graphs and some graphs obtained through graph operations. Also, we try to develop an algorithm to construct a new class of graph with DE energy equal to one. Further, we made an attempt to discover few graphs with DE energy equal to one. Also, an upper bound for the eigenvalues of DE matrix is obtained.