Cupressus sempervirens Essential Oil: Exploring the Antibacterial Multitarget Mechanisms,Chemcomputational Toxicity Prediction,and Safety Assessment in Zebrafish Embryos

Nowadays, increasing interest has recently been given to the exploration of new food preservatives to avoid foodborne outbreaks or food spoilage. Likewise, new compounds that substitute the commonly used synthetic food preservatives are required to restrain the rising problem of microbial resistance. Accordingly, the present study was conducted to examine the chemical composition and the mechanism(s) of action of the Cupressus sempervirens essential oil (CSEO) against Salmonella enterica Typhimuriumand Staphyloccocus aureus. The gas chromatography analysis revealed α-pinene (38.47%) and δ-3-carene (25.14%) are the major components of the CSEO. By using computational methods, such as quantitative structure–activity relationship (QSAR), we revealed that many CSEO components had no toxic effects. Moreover, findings indicated that α-pinene, δ-3-carene and borneol, a minor compound of CSEO, could inhibit the AcrB-TolC and MepR efflux pump activity of S. enterica Typhimurium and S. aureus, respectively. In addition, our molecular docking predictions indicated the high affinity of these three compounds with active sites of bacterial DNA and RNA polymerases, pointing to plausible impairments of the pathogenic bacteria cell replication processes. As well, the safety profile was developed through the zebrafish model. The in vivo toxicological evaluation of (CSEO) exhibited a concentration-dependent manner, with a lethal concentration (LC₅₀) equal to 6.6 µg/mL.     

Tubularenes

We report the synthesis and characterization of conjugated, conformationally rigid, and electroactive carbon-based nanotubes that we term tubularenes. These structures are constructed from a resorcin[n_b]arene base. Cyclization of the conjugated aromatic nanotube is achieved in one-pot eight-fold C–C bond formation via Suzuki–Miyaura cross-coupling. DFT calculations indicate a buildup of strain energy in excess of 90 kcal mol⁻¹. The resulting architectures contain large internal void spaces >260 ų, are fluorescent, and able to accept up to 4 electrons. This represents the first scaffolding approach that provides conjugated nanotube architectures.

First scaffolding approach to obtain tubular-shaped contorted aromatic architectures.     

Synthesis and Study of Poly(ether-amide)s Containing Aromatic and Aliphatic Ether-Amine Segment and Isophthalic Acid

The paper describes some physical properties of poly(ether-amide)s (PEAs) prepared by solution polycondensation reaction of ether-amines such as 2,7-bis(4-aminophenoxy) naphthalene, 2,2-bis[4-(4-aminophenoxy)phenyl] propane, 1,4-bis(4-aminophenoxy methyl) cyclohexane and isophthalic acid. Resulting PEAs are high yield and have inherent viscosity ranging between 0.68–0.75 dL/g. The etheramines containing wholly, semi aromatic and aliphatic-aromatic segments were prepared by using two steps reaction. FTIR, ¹H NMR, and elemental analyses were used for characterization of synthetic ether-amines and poly(ether-amide)s. PEAs films were prepared by solution casting technique then their thermal stability and mechanical properties were measured. TGA in nitrogen atmosphere shows that the PEAs are thermally stability, so 10% weight will be lost in the range of 335–358°C. Tensile strength and elongation at break of the PEA films ranged from 71.1–65.0 MPa and 6.48–8.41%, respectively.     

The study of the electrochemical oxidation mechanism of diphenylamine derivatives in dipolar aprotic solvents: III. Effect of acids and bases of different strengths

The effect of addition of different acids and bases in a wide range of concentration on the voltammetric oxidation of both Variamine blue (VB) and 4-aminodiphenylamine (4-ADPA) was examined in acetonitrile (AcN). The oxidation potential values of either wave of both depolarizers were found to depend on the acid or base strength of the additive—relative to the depolarizer and solvent—and on their concentration in solution. Addition of strong acid as CH₃SO₃H resulted in a single oxidation wave at potentials either equal to or more positive than that of the original second wave. Relatively weak acids as picric and pyridinium ion only shifted the oxidation potential of the first wave to more positive values without affecting the general oxidation pattern.On the other hand, strong bases like ethanolamine, resulted in the formation of a preoxidation wave at more negative potential when present in low concentration and a single wave at identical negative potential at high enough concentrations. Bases of comparable strengths, as that of the depolarizer, like pyridine do not form prewaves but only shifted the final single oxidation wave to more negative potential values. Weaker bases like water and ethanol mainly shifted the oxidation potential of the second wave to less positive values.     

Chronology and characteristics of groundwater along the United Arab Emirates-Oman arid region: a guide for regional sustainability

Journal of Radioanalytical and Nuclear Chemistry - Estimating groundwater recharge rate is essential for water sustainability of the arid region of the United Arab Emirates that receives most...     

A Quasi-Analytical Study of the Nonrelativistic Two-Center Coulomb Problem

The Schr?dinger equation with a pertaining two-center mean field potential scheme is solved by the quasi-analytical ansatz methodology. The ground-state wave function and the corresponding energy of a nonrelativistic nucleon moving in the fields of two fixed Coulomb centers are reported and the behavior of the energy vs. engaged parameters is depicted via illustrative figures.     

Scattering of Klein–Gordon particles by a Kink-like potential

The Klein–Gordon equation for the non-minimal vector and a scalar Kink-like potential is solved in terms of the hypergeometric functions. The scattering problem, i.e. the transmission and reflection coefficients, is studied as well.     

Open problems in some competition models

We present open problems and conjectures for some two-dimensional competition models, namely the logistic competition model and a Ricker-type competition model.