Handique Girls College

Pharmaceuticals as emerging contaminants (EC) in water are one of the major challenges for the future. In this context, the reactivity of selective ECs such as ibuprofen, paracetamol, aspirin, metronidazole, and metoprolol, and their interaction with 4-nitrotoluene (4-NT) are discussed in the light of density functional theory (DFT). The analysis highlights the favorable formation of 4-NT–EC complexes with interaction energies within the range of –13.18 to–6.28 kcalmol−1. The complex formation is exothermic and occurs via non-covalent interactions. Effective interaction leads to changes in the energy of molecular orbitals (MOs) and subsequent alterations in global reactivity descriptors. QTAIM and NCI analyses have also suggested the presence of van der Waals forces between 4-NT and ECs. The findings of this work provide a theoretical basis for future studies on wastewater treatment and the adsorption of ECs onto nitro-substituted materials.

The interaction of main group metal ions [(M(I/II)] specifically Li(I), Na(I), K(I), Be(II), Mg(II) and Ca(II) ions with Furan (Fur) are studied through its exposed π-surface and lone pair of O-atom (LP O) using density functional theory (DFT). The interaction via both the considered modes is strong enough to stabilize 1:1 [M(I/II):Fur] and 1:2 [M(I/II):2Fur] type adducts. Formation of cation-π (12.13 to 291.02 kcalmol-1) adducts are more favourable than cation-lone pair (11.80 to 284.40 kcalmol-1) adducts. The interactions are thermodynamically favourable, and enthalpy and free energy driven. Presence of solvent phase resulted remarkable weakening of the adducts; strength of the interaction is inversely related to the solvent dielectrics. There exist a moderately strong relationship and a strong linear relationship between stability and second order perturbation energy [E(2)] of primary donor-acceptor interaction, and stability and electron density of the adducts, respectively. SAPT0 calculations determined nature of the interactions depending on the positions of interacting species, suggesting considerable contribution of covalent component in stabilizing Be(II) adducts. QTAIM and NCI analyses also performed to validate the major role on ionic interaction in stabilizing the other adducts.

Muga silk (from the silkworm Antheraea assamensis) derived muga nanosilk (MNS) modified glassy carbon electrode was fabricated as a green and sustainable approach for the sensitive electrochemical detection of L-ascorbic acid (L-AA). The prepared muga nanosilk (MNS) has been successfully characterized through techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) techniques. The proposed electrochemical sensor showed linearity towards ascorbic acid within a concentration range of 2–24 µM, while its quantitative working concentration range was found to be from 4.12 to 24 µM. The fabricated electrochemical sensor attained a LOD value of 1.36 µM and an LOQ value of 4.12 µM, along with high sensitivity value of 185 µA mM−1 cm−2. The fabricated sensor proved satisfactory performance in terms of high repeatability (RSD = 4.4%, n = 3) and accuracy (recovery = 98.0%). Furthermore, it exhibited excellent operational and storage stability, retaining approximately 93% of its initial response after 100 consecutive cyclic voltammetry cycles and approximately 90% after 14 days of storage. The practical application of the MNS-modified electrode was verified by the successful detection of ascorbic acid in real samples with good recovery results. Compared with the electrochemical sensors based on other modified electrodes reported previously, the MNS-based electrochemical sensor proposed here has comparable analytical sensitivity but the advantages of the biomaterial-based and eco-friendly electrode modifier. This work has demonstrated the potential of the use of muga nanosilk as a promising functional material for the development of reliable eco-friendly electrochemical sensors for the detection of low concentrations of ascorbic acid.

Biomass-derived biolubricants offer an environmentally sustainable solution to shift from conventional mineral-based lubricants, addressing growing concerns over increasing carbon footprint, resource depletion, climate and environmental impact. This review systematically evaluates how application of various nanomaterials as both additives and heterogeneous catalysts improve the physiochemical properties, catalytic efficiency, tribological and rheological properties of biolubricants synthesized from edible and non-edible vegetable oils. A systematic literature search was conducted using Web of Science, Scopus and Google Scholar for studies published during 2015–2026 following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework. The identified records were screened and selected according to predefined inclusion and exclusion criteria, and a total of 104 studies were included in the final review. The analysis established that nano additives provide excellent lubricity to vegetable oils by reducing friction and wear, while nanocatalysts enable fruitful yield of biodegradable polyol esters. By combining nanotechnology and renewable feedstocks, this review contributes theoretical insights into the recent developments in production of sustainable and high performed biolubricants. Future research should focus on development of sustainable bio-derived nanoadditives, improved nanoadditive dispersion and surface functionalization, comprehensive life-cycle and environmental toxicity assessment, and scalable catalyst/nanoadditive recovery and reuse.

Quantitative acoustic characterization of culturally significant vocal performances remains rare for South Asian traditions, leaving open whether such distinctiveness reflects raw spectral difference or structured vocal control. Motivated by the prominence of Mayabini Ratir Bukut, by Zubeen Garg, in Assamese popular music, this study analyzed formant structure, intensity trajectory, and source-filter interaction within the recording, alongside its position in a corpus of 12 recordings spanning five singers, using descriptors extracted from separated vocal stems. Formant frequencies vary significantly across structural segments, peaking in the middle segment rather than progressing monotonically. Harmonic alignment with formant peaks strengthens at the most salient moments, while peak loudness, roughness, and pitch rarely coincide, indicating intensity distributed across distinct dimensions rather than one climax. Fundamental frequency correlates consistently and stably with only the first formant, indicating sustained rather than climax-linked coordination. Relative to the corpus, the recording occupies a mid-range multivariate position and is not a timbral or dynamic outlier; its distinctiveness instead lies in the precision and consistency of its internal vocal coordination rather than any single differentiating descriptor. These findings offer a reproducible, corpus-grounded account that locates the recording's distinctiveness in the organization of vocal control rather than raw acoustic differences from other singers.