Introduction of high valent Mo6+ in Prussian blue analog derived Co-layered double hydroxide nanosheets for improved water splitting

Herein, we report a facile method for synthesizing MoCo-layered double hydroxide (LDH) nanosheets employing Prussian blue analog (PBA) as the precursor. The introduction of Mo in Co-LDH modulates the electronic structure, increases the number of active sites and electrochemical surface area to improve the hydrogen evolution, oxygen evolution, and overall water splitting activity. As a result, PBA-derived Mo_0.25Co_0.75-LDH nanosheets demonstrated 10 mA cm^?2 current density at only 220 mV and 115 mV overpotentials for OER and HER, respectively. The overall water splitting was attained at 1.52 V cell voltage for 10 mA cm^?2 current density.     

Atomistic De-novo Inhibitor Generation-Guided Drug Repurposing for SARS-CoV-2 Spike Protein with Free-Energy Validation by Well-Tempered Metadynamics

Computational drug design is increasingly becoming important with new and unforeseen diseases like COVID-19. In this study, we present a new computational de novo drug design and repurposing method and applied it to find plausible drug candidates for the receptor binding domain (RBD) of SARS-CoV-2 (COVID-19). Our study comprises three steps: atom-by-atom generation of new molecules around a receptor, structural similarity mapping to existing approved and investigational drugs, and validation of their binding strengths to the viral spike proteins based on rigorous all-atom, explicit-water well-tempered metadynamics free energy calculations. By choosing the receptor binding domain of the viral spike protein, we showed that some of our new molecules and some of the repurposable drugs have stronger binding to RBD than hACE2. To validate our approach, we also calculated the free energy of hACE2 and RBD, and found it to be in an excellent agreement with experiments. These pool of drugs will allow strategic repurposing against COVID-19 for a particular prevailing conditions.     

Nonparaxial effects on the propagation and scattering of a polarized optical pulse

Propagation characteristics of a polarized optical solitary pulse are analyzed by taking into account the effect of nonparaxiality and mutual interaction. To start with, a pair of generalized nonlinear Schrodinger equations is deduced through an operator approach. Stationary solutions of such a system are then analyzed numerically through a boundary value problem in two stages, with and without the nonparaxial effect. In the second stage, the propagating form of the corresponding spatial soliton is studied by an extended split step algorithm ETDRK. The initial profile is considered to be both a one- and two-soliton solution, to visualize the event of scattering and fusion. From this data, we have computed the intensity, root mean square spectral width, and chirp of a single soliton as it propagates. In the case of the two-soliton solution, we observe that for source parameter values, the fusion is more favored than scattering. It is observed that nonparaxiality and the interaction between A(x) and A(y) tends to destroy the periodic behaviors of these parameters. Lastly, we have investigated the modulational instability of the system as function of frequency detuning and nonparaxiality. The form of the gain is discussed as a function of nonparaxiality.     

Theoretical modeling of Cu(II), Sr(II), Gd(III), U(VI) sorption from nuclear effluent on PHA resin with experimental validation

Journal of Radioanalytical and Nuclear Chemistry - The sorption capacity of an in–house synthesized novel resin Polyhydraxamic acid(PHA) towards Cu(II), Sr(II), Gd(III), U(VI) ions was...     

A Molecular Strategy to Lock‐in the Conformation of a Perylene Bisimide‐Derived Supramolecular Polymer

Locking‐in the conformation of supramolecular assemblies provides a new avenue to regulate the (opto)electronic properties of robust nanoscale objects. In the present contribution, we show that the covalent tethering of a perylene bisimide (PBI)‐derived supramolecular polymer with a molecular locker enables the formation of a locked superstructure equipped with emergent structure–function relationships. Experiments that exploit variable‐temperature ground‐state electronic absorption spectroscopy unambiguously demonstrate that the excitonic coupling between nearest neighboring units in the tethered superstructure is preserved at a temperature (371 K) where the pristine, non‐covalent assembly exists exclusively in a molecularly dissolved state. A close examination of the solid‐state morphologies reveals that the locked superstructure engenders the formation of hierarchical 1D materials which are not achievable by unlocked assemblies. To complement these structural attributes, we further demonstrate that covalently tethering a supramolecular polymer built from PBI subunits enables the emergence of electronic properties not evidenced in non‐covalent assemblies. Using cyclic voltammetry experiments, the elucidation of the potentiometric properties of the locked superstructure reveals a 100‐mV stabilization of the conduction band energy when compared to that recorded for the non‐covalent assembly.     

Metal‐like Ductility in Organic Plastic Crystals: Role of Molecular Shape and Dihydrogen Bonding Interactions in Aminoboranes

Ductility is a common phenomenon in many metals but is difficult to achieve in molecular crystals. Organic crystals bend plastically on one or two face‐specific directions but fracture when stressed in any other arbitrary directions. An exceptional metal‐like ductility and malleability in the isomorphous crystals of two globular molecules, BH₃NMe₃ and BF₃NMe₃, is reported, with characteristic tensile stretching, compression, twisting, and thinning. The mechanically deformed samples, which transition to lower symmetry phases, retain good long‐range order amenable to structure determination by single‐crystal X‐ray diffraction. Molecules in these high‐symmetry crystals interact through electrostatic forces (B^??N⁺) to form columnar structures with multiple slip planes and weak dispersive forces between columns. On the other hand, the limited number of facile slip planes and strong dihydrogen bonding in BH₃NHMe₂ negates ductility. Our study has implications for the design of soft ferroelectrics, solid electrolytes, barocalorics, and soft robotics.     

Surface Functionalization of Magnetite Nanoparticles with Multipotent Antioxidant as Potential Magnetic Nanoantioxidants and Antimicrobial Agents

Functionalized magnetite nanoparticles (Fe₃O₄) were prepared using the coprecipitation method followed by functionalization with a multipotent antioxidant (MPAO). The MPAO was synthesized and analyzed using FTIR and NMR techniques. In this study, the functionalized nanoparticles (IONP@AO) were produced and evaluated using the FTIR, XRD, Raman, HRTEM, FESEM, VSM, and EDX techniques. The average determined particle size of IONP@AO was 10 nanometers. In addition, it demonstrated superparamagnetic properties. The magnitude of saturation magnetization value attained was 45 emu g⁻¹. Virtual screenings of the MPAO’s potential bioactivities and safety profile were performed using PASS analysis and ADMET studies before the synthesis step. For the DPPH test, IONP@AO was found to have a four-fold greater ability to scavenge free radicals than unfunctional IONP. The antimicrobial properties of IONP@AO were also demonstrated against a variety of bacteria and fungi. The interaction of developed nanoantioxiants with biomolecules makes it a broad-spectrum candidate in biomedicine and nanomedicine.     

Unusual Surface Latent Heat Flux Variations and Their Critical Dynamics Revealed before Strong Earthquakes

We focus on the possible thermal channel of the well-known Lithosphere–Atmosphere–Ionosphere Coupling (LAIC) mechanism to identify the behavior of thermal anomalies during and prior to strong seismic events. For this, we investigate the variation of Surface Latent Heat Flux (SLHF) as resulting from satellite observables. We demonstrate a spatio-temporal variation in the SLHF before and after a set of strong seismic events occurred in Kathmandu, Nepal, and Kumamoto, Japan, having magnitudes of 7.8, 7.3, and 7.0, respectively. Before the studied earthquake cases, significant enhancements in the SLHF were identified near the epicenters. Additionally, in order to check whether critical dynamics, as the signature of a complex phenomenon such as earthquake preparation, are reflected in the SLHF data, we performed a criticality analysis using the natural time analysis method. The approach to criticality was detected within one week before each mainshock.