S.N. Bose National Centre for Basic Sciences

The Main Aim of this paper is to explain the emergence of new components of pulsars at higher radio bands by implementing the Inverse Compton Scattering Mechanism. From pulsar radio observation, it is seen that a couple of pulsars reveal new emission components at higher radio frequencies, although they show single-component emission at lower frequencies. We develop a brief outline, fostering inverse Compton scattering (ICS) of the low-frequency radio photons as a vulnerable source of scattering, susceptible to explaining the evolution of new components of some radio pulsars at higher bands. We couple the conventional curvature radiation (CR) mechanism and ICS, and suggest that the spectral convolution of the flux component individually from CR and the modulated template due to the ICS scattered component can be combined to reproduce such signatures associated with the diverse morphology of the integrated pulse profile. We reproduce the beam frequency diagram, the geometrical variation of different parameters of the emission geometry, as well as the multi-frequency evolution from theory. We have suitably tuned the input parameter space and given the combination of parameters that can tune to a particular scattered frequency in tabulated form. We conclude that ICS may be a responsible process for describing the emergence of new components in higher radio emission bands.

The rational design of superhydrophobic solid acid catalysts with enhanced chemical stability is critical for overcoming water-induced deactivation in biodiesel synthesis. Herein, we developed a novel etherified sulfonic acid-functionalized activated...

Abstract We present an analysis of temporal starspot evolution and its distribution on an active rapid rotator ( P rot = 1.22 days), TIC 272272592, using high-precision time-series photometry from the Transiting Exoplanet Survey Satellite spanning over 3 yr. The primary objective of this work is to study the distribution pattern of starspots across the stellar surface and to investigate the spot evolution over time. This is a fascinating object, being a rapid rotator with a decline flare rate (∼0.5 dex) over 4 yr of Kepler observation. Therefore, we performed starspot modeling on this object using Best rAandom StarSpots Model calculAtioN software, and the analysis indicates the presence of two spots on the stellar surface, with a stable high-latitude spot and occasionally a small midlatitude spot. Over time, the midlatitude spot exhibits a gradual high-latitude migration, suggesting latitudinal evolution. Moreover, our analysis reveals a moderate negative correlation of starspot sizes with time (Spearman ρ = −0.43), suggesting a significant decay across the 3 yr baseline, though no clear cyclic pattern is detected. The spot groups persist for several years, with mean total spot size in sectors 14, 15, 41, 54, and 55 of 5.1%, 5.7%, 5.5%, 4.8%, and 4.4%, respectively. Additionally, we have estimated the peak flare temperature of 36 detected flares between 11,000 ± 1900 K and 24,700 ± 5000 K, and 70% of the flares exhibited peak emitting area of flares within the range from 170 ppm to 563 ppm. Furthermore, no statistically significant correlation was found between stellar flares with rotational phase for this object.

Despite demonstrating bistability in spin-crossover (SCO) materials, the absence of long-range magnetic order and poor electrical conductivity limit their prospect in spintronic and nanoelectronic applications. Intending to create hybrid devices made of SCO-2D architecture, here, we report an easily processable Fe-based SCO nanostructures grown on 2D reduced graphene oxide (rGO). X-ray photoelectron spectra of the hybrid clearly reveal the formation of new bonding state with possible charge transfer between rGO and SCO nanoparticles. This interfacial charge transfer enhances intermolecular interactions, resulting in increased cooperativity within the heterostructure. The temperature dependent Mössbauer spectra analysis distinctly uncovers the proportion of Fe (II) spin states within the hybrid nanocomposite samples, highlighting how the formation of a 2D network of SCO clusters enhances the cooperativity. Notably, both the thermal hysteresis and the mean spin-transition temperature are tunable through the application of a magnetic field, underscoring significant magnetic interactions. The inherently low conductivity of pristine SCO nanostructures is addressed by embedding them within a conductive rGO matrix. This facilitates the electrical detection of magnetic bistability through high-spin/low-spin conductance switching, even in the absence of an external magnetic field. As a result, spin functionality is integrated into the conductance behavior, paving the way for hybrid 2D spintronic devices. Finally, ab-inito calculations, on the experimentally motivated model systems provide insights into the microscopic mechanism confirming the enhanced magnetic interaction in the hybrid architecture facilitated by interfacial charge transfer.

By employing computational methods, the authors have demonstrated that dimensionality reduction provides an effective strategy for engineering electronic and magnetic structures. Specifically, starting from the bulk Kagome parent compound RMn${}_{6}$Sn${}_{6}$ (R = Lu, Mg), this approach has led to the design of ferromagnetic thin films RMn${}_{6}$Sn${}_{8}$, where the RKKY interaction stabilizes robust ferromagnetism. These films exhibit Weyl states, nontrivial band crossings, large Berry curvature, and a pronounced anomalous Hall effect. As Kagome metallic Weyl ferromagnets, these 2D structures combine strong magnetism with nontrivial topology, offering pathways for spintronics, low-power memory, Hall sensors, and energy-efficient device engineering.

The ability of individual Watson-Crick (WC) base pair (bp) in duplex DNA to transition to alternative pairing modes, such as Hoogsteen (HG) bp, on biologically relevant time scales has significantly influenced DNA research for many years. Such bp transitions in the presence of proteins are not well documented in the literature. Here, we employ the well-tempered metadynamics (WT-MetaD) method to determine the lowest free energy path for the transition between WC and HG bp in naked DNA to standardize our protocol of using the glycosidic angle (χ) as collective variable (CV) and reproduce previously reported experimental and simulation data. We use these protocols for the bp transition in the presence of proteins. For the transition between WC → HG bp, the energy barrier decreases to approximately 8 kcal/mol in the presence of proteins compared to naked DNA, and the HG bp becomes ∼4.0 kcal/mol more stable than the WC bp. In contrast, for the reverse HG → WC transition, the energy barrier increases to nearly 12 kcal/mol, with the HG bp remaining ∼3 kcal/mol more stable than its WC counterpart.