New Synthetic Route for Reaching Higher Phase Stabilization in LAMOX-Based Electrolyte for Solid Oxide Fuel Cells

S-substituted La₂Mo₂O₉ were synthesized by a solid-state procedure employing ammonium sulfate (NH₄)₂SO₄ as a sulfur source. The synthesized powders were examined using X-ray diffraction (XRD), thermogravimetric analysis (TGA), infrared, and Raman spectroscopies. The results divulged that the stabilization of the β-La₂Mo₂O₉ polymorph occurred in the interval of sulfur composition 0.1≤y≤0.6. This substitution generates a linear dwindling of the unit cell volume. The decomposition of all substituted samples started above 900 °C with a total weight loss linearly dependent on the sulfur content. Electrical studies confirmed that substituting S⁶⁺ for Mo⁶⁺ suppresses the phase transition of La₂Mo₂O₉ and stabilizes the cubic polymorph down to ambient temperature. It was also remarkable that this substitution caused a decrease in the conductivity, and unfortunately, none of the tested compositions allowed exceeding the conductivity of La₂Mo₂O₉. Infrared and Raman spectra confirmed the presence of the characteristic peaks of sulfates and molybdates groups.     

Loading of ZIF-67 on silk with sustained release of iodine as biocompatible antibacterial fibers

Antibacterial fibers have great potential in numerous applications, including bandages, surgical robes, and surgical sutures, and play a significant role in our everyday lives. Here, zeolitic imidazolate framework-67 was synthesized using a green method on silk fibers through a layer-by-layer process under ultrasonic irradiation (ZIF-67@silk [U]) and without ultrasonic irradiation (ZIF-67@silk [B]). Then, iodine was loaded on ZIF-67@silk samples and were assessed as antibacterial fibers with iodine release. Four samples of ZIF-67@silk and I₂@ZIF-67@silk were characterized by FT-IR, PXRD, FE-SEM, TGA, BET, and UV–Vis spectroscopy. Finally, antibacterial activity of ZIF-67@silk (B and U) and I₂@ZIF-67@silk (B and U) on Staphylococcus aureus as Gram-positive bacteria and Escherichia coli as Gram-negative bacteria was investigated. In addition to ZIF-67@silk samples, iodine-loaded samples showed excellent antimicrobial facility.     

Inference on periodograms of infinite dimensional discrete time periodically correlated processes

In this work we shall consider two classes of weakly second-order periodically correlated and strongly second-order periodically correlated processes with values in separable Hilbert spaces. The periodogram for these processes is introduced and its statistical properties are studied. In particular, it is proved that the periodogram is asymptotically unbiased for the spectral density of the processes, where the type of the convergence is fully specified.     

Symplectic supercuspidal representations and related problems

In this paper, we summarize the basic structures and properties of irreducible symplectic supercuspidal representations of GLn(F) over a p-adic local field F with characteristic zero, and explore possible topics for further investigation.     

Conjugation of pectin biopolymer with Au-nanoparticles as a drug delivery system: Experimental and DFT studies

In the present study, pectin-coated gold nanoparticles (GNPs) were used as a candidate for curcumin drug delivery. The effect of the size of synthesized GNPs was examined, as an important factor on the yield of drug delivery. For this purpose, three different sizes of GNPs were first synthesized using a chemical method. The synthesized nanoparticles were then coated with pectin biopolymer. Finally, curcumin drug was loaded in a pectin@GNPs complex. Various methods such as UV–vis spectrophotometry, dynamic light scattering, scanning electron microscopy and Fourier-transform infrared spectroscopy were used to characterize the synthesized GNPs and pectin@GNPs. The encapsulation efficiency and the release percentage of the drug were calculated for two different pH values. Further, an antibacterial study was conducted. The results revealed that 100 nm GNPs had the highest encapsulation efficiency. An investigation of the release rate of curcumin drug at 37°C for 48 h indicated that the amount of drug released was higher in acidic pH than at pH 7.4 with a slow release rate. The electronic structure and the adsorption properties of pectin–GNPs complex were examined using the density functional theory method.     

Computational investigation of the strategy of DNA/RNA stabilization through the study of the conjugation of an oligonucleotide with silver and gold nanoparticles

This research deals with the potential of metallic nanoparticles in DNA/RNA stabilization. In this regard, the interaction of adenosine monophosphate (AMP) as a representative of the nucleotide family was theoretically investigated through density functional theory. AMP is a short form of DNA or RNA macromolecules that can interact with gold (Au) and silver (Ag) nanoparticles. The literature represents the thiolation of oligonucleotides as a suitable way for DNA/RNA adsorption on the stated nanoparticles. In this study, the role of different solvents on the thiolation of AMP is scrutinized. The results showed that acetonitrile is the best solvent for the thiolation of AMP with reaction enthalpy (ΔH) of −66.3 kJ/mol. The adsorption of thiolated adenosine monophosphate (TAMP) on the surface of Ag/Au nanoparticles (Ag/AuNP) was studied in different solvents, and in the gas phase. Our results revealed the interaction of TAMP with adsorption energies of −65.3 and −74.1 kJ/mol (gas phase), −54.8 and −62.5 kJ/mol (acetonitrile), and −59.2 and −70.6 kJ/mol (water) on AgNPs and AuNPs, respectively. AuNPs have a shorter bond distance in adsorption of TAMP compared to AgNPs (2.61 vs. 2.78 Å). For all systems, the frontier molecular orbital, the electronic charge passed through the nanoparticles, the density of states, and the molecular electrostatic potential were investigated. The results confirm the suitability of these nanoparticles as carriers for nucleotides that may be useful in gen delivery applications.     

Integrating thermal-concentration smoothed profile with lattice Boltzmann methods for simulating sedimentation of nonisothermal circular particles

A thermal-concentration smoothed profile-lattice Boltzmann method is proposed to study the effect of the concentration field on the dynamic behavior of nonisothermal cylindrical particles during the sedimentation process. The velocity, temperature, and concentration equations are solved using the lattice Boltzmann method. Moreover, the smoothed profile method is employed to enforce the nonslip boundary condition as well as constant temperature and constant concentration boundary conditions at the particles surfaces. Moreover, the Boussinesq approximation is used to couple the velocities, temperatures, and concentrations fields. The proposed combined method is validated by comparing the present numerical results with those found in the literature, showing good consistency. Then, the effect of the concentration buoyancy on the behavior of nonisothermal particles is discussed. In addition, the effect of Prandtl, Schmidt, and thermal Grashof numbers on the settling process is investigated. The results show that, by adding the effect of concentration, the maximum settling velocity of hot particles is reduced more relative to the cold ones; accordingly, the cold particles are settled faster than the hot ones. Finally, the sedimentation of two particles in a container at high thermal Grashof is investigated. It is shown that, at high thermal Grashof, there is an intense competition between the buoyancy force and gravity for the hot particles. The buoyancy flow generated leads to the reversal of the drafting-kissing-tumbling motion of the hot particles, making the particles move upward.     

A note on the independent domination number in graphs

We obtain an upper bound for the independent domination number of a graph in terms of the domination number and maximum degree.     

Characterizations of higher-order convexity properties with respect to Chebyshev systems

In this paper various notions of convexity of real functions with respect to Chebyshev systems defined over arbitrary subsets of the real line are introduced. As an auxiliary notion, a concept of a relevant divided difference and also a related lower Dinghas type derivative are also defined. The main results of the paper offer various characterizations of the convexity notions in terms of the nonnegativity of a generalized divided difference and the corresponding lower Dinghas type derivative.     

Synthesis and structural characterization of three dinuclear Copper(II) complexes incorporating pyrazolyl-derived ligands

Three new binuclear copper complexes of formulae $ \left[ {{\text{Cu}}_{2}^{\text{II}} {\text{Pz}}_{2}^{\text{Me3}} {\text{Br}}_{ 2} \left( {{\text{PPh}}_{ 3} } \right)_{ 2} } \right] $ (1), $ \left[ {{\text{Cu}}_{ 2}^{\text{II}} {\text{Pz}}_{2}^{\text{Ph2Me}} {\text{Cl}}_{ 2} \left( {{\text{PPh}}_{ 3} } \right)_{ 2} } \right] $ (2) and $ \left[ {{\text{Cu}}_{2}^{\text{II}} \left( {{\text{Pz}}^{\text{PhMe}} } \right)_{ 4} {\text{Cl}}_{ 4} } \right] $ (3) (Pz^Me3?=?3,4,5-trimethylpyrazole, Pz^Ph2Me?=?4-methyl-3,5-diphenylpyrazole and Pz^PhMe?=?3-methyl-5-phenylpyrazole) have been synthesized and characterized by chemical analysis, FTIR and ³¹P NMR spectroscopy and single-crystal X-ray diffraction. Complex 1 is a doubly bromo-bridged dimer, while complexes 2 and 3 are chloro-bridged dimers. The Cu(II) centers are in a distorted tetrahedral geometry for 1 and 2 and a distorted square pyramidal N₂Cl₃ environment for 3.