Experimental study of structure and dynamics in a monolayer of paramagnetic colloids confined by parallel hard walls

We study the structural and dynamical properties of paramagnetic colloidal spheres interacting as repulsive dipoles in two dimensions and confined between parallel hard walls. We observed that the structure and dynamics of the self-assembled colloids are strongly dependent upon the width of the confining channel. The system exhibits re-entrant behavior as a function of the channel width, transitioning from solid-like to liquid-like repeatedly in excellent agreement with simulation results. For large channels, an ordered layered structure self-assembles near the walls, but this local structure is not commensurate with the bulk structure, leading to localized stable defects.     

Can nonlinear elasticity explain contact-line roughness at depinning?

We examine whether cubic nonlinearities, allowed by symmetry in the elastic energy of a contact line, may result in a different universality class at depinning. Standard linear elasticity predicts a roughness exponent zeta = 1/3 (one loop), zeta = 0.388 +/- 0.002 (numerics) while experiments give zeta approximately = 0.5. Within functional renormalization group methods we find that a nonlocal Kardar-Parisi-Zhang-type term is generated at depinning and grows under coarse graining. A fixed point with zeta approximately = 0.45 (one loop) is identified, showing that large enough cubic terms increase the roughness. This fixed point is unstable, revealing a rough strong-coupling phase. Experimental study of contact angles theta near pi/2, where cubic terms in the energy vanish, is suggested.     

Effect of thickness on the optoelectronic properties of electrodeposited nanostructured SnS films

The present study focuses on the effect of film thickness on the physical properties of tin mono-sulfide (SnS) nanostructures deposited through an electrodeposition technique. The SnS films were characterized using X-ray diffraction (XRD) analysis, which confirmed the formation of polycrystalline orthorhombic SnS thin films. The crystallite size and lattice parameters were estimated from the XRD patterns. The effect of the deposition voltage on the surface morphology of the deposited films was evaluated by field emission electron microscopy (FESEM). The FESEM images revealed that the nanostructures possess plate-like and bulky pyramid morphologies. Also, optical plots of the thin films were considered, which determined the direct band gap energies of the samples as 1.42–1.50 eV. Finally, Mott–Schottky measurements indicated that the samples have p-type conductivity and the carrier concentrations of the SnS films improve with the increase of their thicknesses.     

A New Algorithm for Digital Image Encryption Based on Chaos Theory

In recent decades, image encryption, as one of the significant information security fields, has attracted many researchers and scientists. However, several studies have been performed with different methods, and novel and useful algorithms have been suggested to improve secure image encryption schemes. Nowadays, chaotic methods have been found in diverse fields, such as the design of cryptosystems and image encryption. Chaotic methods-based digital image encryptions are a novel image encryption method. This technique uses random chaos sequences for encrypting images, and it is a highly-secured and fast method for image encryption. Limited accuracy is one of the disadvantages of this technique. This paper researches the chaos sequence and wavelet transform value to find gaps. Thus, a novel technique was proposed for digital image encryption and improved previous algorithms. The technique is run in MATLAB, and a comparison is made in terms of various performance metrics such as the Number of Pixels Change Rate (NPCR), Peak Signal to Noise Ratio (PSNR), Correlation coefficient, and Unified Average Changing Intensity (UACI). The simulation and theoretical analysis indicate the proposed scheme’s effectiveness and show that this technique is a suitable choice for actual image encryption.     

Synthesis and Cytotoxic Activity of Some Novel Dihyrobenzo[h]pyrano[3,2‐c]chromene Derivatives

Three‐component reaction of 4‐hydroxy‐2H‐benzo[h]chromen‐2‐one, aromatic aldehydes, and malononitrile in the presence of 1,4‐diazabicyclo[2.2.2]octane (DABCO) in ethanol at room temperature affords good yields of novel dihyrobenzo[h]pyrano[3,2‐c]chromene derivatives. The synthesized compounds examined by MTT assays for cytotoxic activity in two human cancer cell lines (MOLT‐4, HL‐60). Most of the evaluated compounds showed low inhibitory activity against tumor cell line at micromolar concentrations.     

Tailoring magnetism in quantum dots

We study magnetism in magnetically doped quantum dots as a function of the confining potential, particle numbers, temperature, and strength of the Coulomb interactions. We explore the possibility of tailoring magnetism by controlling the nonparabolicity of the confinement potential and the electron-electron Coulomb interaction, without changing the number of particles. The interplay of strong Coulomb interactions and quantum confinement leads to enhanced inhomogeneous magnetization which persists at higher temperatures than in the noninteracting case. The temperature of the onset of magnetization can be controlled by changing the number of particles as well as by modifying the quantum confinement and the strength of the Coulomb interactions. We predict a series of electronic spin transitions which arise from the competition between the many-body gap and magnetic thermal fluctuations.     

Noncontact racK and pinion powered by the lateral Casimir force

The lateral Casimir force is employed to propose a design for a potentially wear-proof rack and pinion with no contact, which can be miniaturized to the nanoscale. The robustness of the design is studied by exploring the relation between the pinion velocity and the rack velocity in the different domains of the parameter space. The effects of friction and added external load are also examined. It is shown that the device can hold up extremely high velocities, unlike what the general perception of the Casimir force as a weak interaction might suggest.     

Probing the solvent-induced tautomerism of a redox-active ureidopyrimidinone

A ferrocene-functionalised ureidopyrimidinone has been synthesised that can signal the solvent-induced tautomerism of the dimeric 4[1H]-pyrimidinone form to the monomeric 6[1H]-pyrimidinone form.     

Tuneable side-chain supramolecular polymer

[reaction: see text] A random copolymer containing 1,5-dialkyloxynaphthalene moieties has been synthesized using atom-transfer radical polymerization. We have shown that this polymer has the ability to form complexes with the tetracationic cyclophane cyclobis(paraquat-p-phenylene) (CBPQT(4+)) and that electrochemical reduction of the cyclophane or the addition of a competing guest for the cavity of the cyclophane results in disassembly of the supramolecular polymer.     

Andrographolide: A Herbal-Chemosynthetic Approach for Enhancing Immunity,Combating Viral Infections,and Its Implication on Human Health

Plants consistently synthesize and accumulate medically valuable secondary metabolites which can be isolated and clinically tested under in vitro conditions. An advancement with such important phytochemical production has been recognized and utilized as herbal drugs. Bioactive andrographolide (AGL; C₂₀H₃₀O₅) isolated from Andrographis paniculate (AP) (Kalmegh) is a diterpenoid lactones having multifunctional medicinal properties including anti-manic, anti-inflammatory, liver, and lung protective. AGL is known for its immunostimulant activity against a variety of microbial infections thereby, regulating classical and alternative macrophage activation, Ag-specific antibody production during immune disorder therapy. In vitro studies with AGL found it to be effective against multiple tumors, neuronal disorders, diabetes, pneumonia, fibrosis, and other diverse therapeutic misadventures. Generally, virus-based diseases like ZIKA, influenza A virus subtype (H1NI), Ebola (EBOV), Dengue (DENV), and coronavirus (COVID-19) epidemics have greatly increased scientific interest and demands to develop more effective and economical immunomodulating drugs with minimal side effects. Trials and in vitro pharmacological studies with AGL and medicinally beneficial herbs might contribute to benefit the human population without using chemical-based synthetic drugs. In this review, we have discussed the possible role of AGL as a promising herbal-chemo remedy during human diseases, viral infections and as an immunity booster.