Malda College

Background India, currently in the sustained phase of visceral leishmaniasis elimination, continues to face challenges due to reports of indigenous cases from emerging foci, detection of parasitic DNA in multiple sand fly species, and the potential involvement of animal reservoirs in disease transmission. Although Leishmania donovani has traditionally been regarded as anthroponotic, domestic animals may play an under-recognized role in maintaining transmission. Methods A multicentric study was conducted across seven districts in endemic (Bihar, Jharkhand, West Bengal) and emerging foci (Kerala, Tamil Nadu) states. A total of 782 domestic animals (dogs, goats, cattle, and cats) were screened using rK39 serology, microscopy, and quantitative PCR targeting Leishmania kinetoplast DNA. Species confirmation was performed by ITS1-PCR and sequencing. Sand flies were examined for natural infection, and COI barcoding was used for blood-meal analysis. Results Amastigotes were microscopically confirmed in canine samples. Overall, out of 782 domesticated animals screened, 98 animals were rK39 seropositive. Leishmania DNA was detected by qPCR in 129 animals, of which 81 were confirmed by ITS1-PCR across dogs, goats, cattle, and one cat; 21 samples were sequenced and identified as L. donovani. Natural infection with L. donovani was also confirmed in Phlebotomus argentipes, which also feeds on domesticated animals like cattle. Conclusion These findings provide molecular and serological evidence of L. donovani infection in multiple domestic animal species, suggesting the potential involvement of a zoonotic transmission cycle. Sustained success of India's kala-azar elimination program will require holistic integrated surveillance systems that include domestic animal reservoirs in addition to human and vector populations.

An inclusion complex between the anticancer drug 5-fluoro-2′-deoxyuridine (FdUrd) and β-cyclodextrin (β-CD) was prepared using a co-precipitation method and systematically characterized. Complex formation was examined by ^1H NMR, FTIR, UV–Vis, fluorescence spectroscopy, and ESI-MS, with additional morphological analysis by scanning electron microscopy. Job’s plot confirmed a 1:1 host–guest stoichiometry, and the binding constant determined by the Benesi–Hildebrand method was 2.43 × 10³ M⁻¹ at 298 K, corresponding to a standard Gibbs free energy change (ΔG°) of −4.61 kcal·mol⁻¹, indicating a thermodynamically favorable inclusion process. Density functional theory calculations and molecular docking provided insight into the stabilization and plausible orientation of FdUrd within the β-CD cavity. In vitro cytotoxicity studies against A549 lung cancer cells showed that the inclusion complex exhibited enhanced activity (IC₅₀ = 28.22 ± 7.86 µg·mL⁻¹) compared with free FdUrd (IC₅₀ = 44.10 ± 7.98 µg·mL⁻¹), while β-CD alone displayed negligible cytotoxicity. The inclusion complex also demonstrated improved antioxidant and antimicrobial activity relative to the uncomplexed drug. These results indicate that β-CD inclusion modulates the physicochemical and biological behavior of FdUrd without chemical modification of the drug molecule.

This work presents a detailed investigation of anisotropic superdense compact stellar configurations within the framework of modified f(R, T) gravity by employing the well-known Vaidya–Tikekar (VT) metric ansatz. Assuming a linear form of the gravitational Lagrangian, f(R,T)=R+2β T , where β denotes the matter–geometry coupling parameter, the modified field equations are derived using the variational principle. The imposition of the vanishing complexity condition on an uncharged anisotropic matter distribution enables the determination of the complementary metric potential, leading to an exact and physically viable interior solution. The interior spacetime is smoothly matched to the exterior Schwarzschild solution through the continuity of the metric functions and the vanishing of radial pressure at the stellar boundary, allowing the evaluation of model parameters for observed stellar masses and radii. As an input the pulsar 4U 1608 –52 ( 1.57^+0.30_-0.29 M_⊙, 9.8^+1.8_-1.8 km) is considered for detailed graphical analysis, while additional compact stars—Her X-1, LMC X-4, 4U 1538 –52, Cen X-3, SMC X-4, and EXO 1785–248—are examined numerically presented in tabular form to assess the robustness of the model. Two complementary scenarios are explored: (i) variation of the coupling parameter β with a fixed spheroidal parameter K, and (ii) variation of K while keeping β constant. In both cases, the metric potentials are regular and free from singularities, and the energy density along with the radial and tangential pressures remains positive, continuous, and monotonically decreasing, with the radial pressure vanishing at the stellar surface. The positive anisotropy factor contributes a repulsive force that supports equilibrium against gravitational collapse. The model satisfies all fundamental physical requirements, including the null, weak, strong, and trace energy conditions. Stability analyses confirm that the causality condition is maintained, with both radial and tangential sound speeds remaining below the speed of light, while Herrera’s cracking criterion indicates stable configurations. Moreover, the adiabatic index exceeds the critical value of 4/3 throughout the stellar interior, ensuring dynamical stability. The equilibrium of the system is further validated through the Tolman–Oppenheimer–Volkoff (TOV) equation, demonstrating a precise balance among gravitational, hydrostatic, and anisotropic forces. Our findings reveal that negative values of the coupling parameter β lead to denser and more compact stellar configurations, thereby enhancing the overall stability of the system. Stability is also maintained for a range of spheroidal parameters K=-0.6 , -0.7 , -0.85 , and -1 , with increasingly negative values of β favored for larger deviations from spherical geometry. Overall, the developed solutions are physically viable, stable, and consistent with observational data, offering valuable insights into relativistic astrophysical phenomena within the context of modified theories of gravity.

Background Despite significant progress in broadening the range of contraceptive choices, the disparity between rural and urban areas in the use of contemporary reversible contraceptives remains a concern in India. Methods Using data from the fifth round of the National Family Health Survey (NFHS-5, 2019–2021), the study addresses the gap by examining rural–urban differences and the underlying factors influencing modern reversible contraceptive uptake. The study includes a sample of 49,046 women of reproductive age who wish to delay their next childbearing within the next 2 years, excluding all missing responses. Using descriptive statistics, bivariate chi-square significance test, and multivariate decomposition analysis, the study intends to address the objectives. Results More than two-thirds of women use some form of modern reversible methods, and the share was higher among urban dwellers (70.67%) than their rural counterparts (65.55%). In particular, around 75% of the rural–urban gap in the uptake was attributed to the socio-demographic characteristics of women. Of these, mass media exposure, level of education, and region of residence were the significant contributors to the gap. Conclusions The study findings underscore the need for interventions aiming at improving media exposure and the level of education among rural dwellers. Additionally, strategic interventions are also important for diminishing the existing rural–urban gap in the eastern and north-eastern regions.

Cavity size plays a decisive role in governing host–guest interactions in cyclodextrin-based inclusion systems. In this study, the encapsulation behavior of 4-aminopyridine (4-AP) with α- and β-cyclodextrins (α-CD and β-CD) was systematically investigated to elucidate the relationship between cavity dimensions, binding thermodynamics, and functional performance. Inclusion complex formation was confirmed by ^1H NMR, UV–visible, FTIR, fluorescence spectroscopy, and ESI–MS analyses, revealing distinct cavity-dependent binding modes. Pronounced upfield shifts of inner cavity protons (H3 and H5), along with guest proton perturbations, indicated deeper inclusion and stronger stabilization of 4-AP within the β-CD cavity compared to α-CD. Thermodynamic parameters demonstrated enhanced binding affinity and stability for the β-CD complex, consistent with its optimal cavity size. Density functional theory (DFT) calculations further corroborated the experimental findings, providing insights into inclusion geometry, interaction energies, and non-covalent stabilization, while reduced density gradient (RDG) analysis confirmed the dominance of van der Waals and hydrogen bonding interactions. In vitro release studies revealed a cavity size–dependent modulation of drug release, with β-CD complexes exhibiting more sustained release profiles relative to α-CD and free 4-AP, indicating improved encapsulation efficiency and controlled delivery behavior. Importantly, biological evaluations demonstrated that cyclodextrin inclusion significantly influences functional activity. Antioxidant and antimicrobial assays showed enhanced activity for the inclusion complexes, particularly for β-CD, compared to the free drug, highlighting the role of improved stability and molecular dispersion. Furthermore, in vitro cytotoxicity studies using A549 human lung adenocarcinoma cells confirmed that β-CD encapsulation leads to superior biological response, attributable to optimized release and stronger host–guest interactions. Overall, this study establishes a direct correlation between cyclodextrin cavity size, binding energetics, release behavior, and biological function, demonstrating that cavity size–dependent control of host–guest interactions can be strategically exploited to enhance drug performance.