Density, Viscosity, Velocity and Refractive Index of Binary Mixtures of Poly(Ethylene Glycol) 200 with Ethanolamine, m-Cresol and Aniline at 298.15 K

Densities, absolute viscosities, ultrasonic velocities and refractive indices of binary mixtures of poly(ethylene glycol) 200 with ethanolamine, m-cresol and aniline have been measured at 298.15 K, under atmospheric pressure, over the entire composition range. The experimental data have been used to calculate acoustic impedance, specific heat ratio and relative association for these binary mixtures. Excess molar volume, deviation in viscosity, deviation in refractive index, deviation in isentropic compressibility, excess acoustical impedance and excess Gibbs energy of activation for viscous flow have been plotted to determine the nature and extent of interaction present in the solutions. The results have been fitted to Redlich-Kister polynomial equation. The results have been explained in terms of specific intermolecular and intramolecular interactions present in the mixtures and are found to support each other. The isothermal compressibility for the binary mixtures was predicted by an equation based on Flory??s statistical theory and three rigid sphere equations.     

Role of Bacillus cereus in Improving the Growth and Phytoextractability of Brassica nigra (L.) K. Koch in Chromium Contaminated Soil

Plant growth-promoting rhizobacteria (PGPR) mediate heavy metal tolerance and improve phytoextraction potential in plants. The present research was conducted to find the potential of bacterial strains in improving the growth and phytoextraction abilities of Brassica nigra (L.) K. Koch. in chromium contaminated soil. In this study, a total of 15 bacterial strains were isolated from heavy metal polluted soil and were screened for their heavy metal tolerance and plant growth promotion potential. The most efficient strain was identified by 16S rRNA gene sequencing and was identified as Bacillus cereus. The isolate also showed the potential to solubilize phosphate and synthesize siderophore, phytohormones (indole acetic acid, cytokinin, and abscisic acid), and osmolyte (proline and sugar) in chromium (Cr⁺³) supplemented medium. The results of the present study showed that chromium stress has negative effects on seed germination and plant growth in B. nigra while inoculation of B. cereus improved plant growth and reduced chromium toxicity. The increase in seed germination percentage, shoot length, and root length was 28.07%, 35.86%, 19.11% while the fresh and dry biomass of the plant increased by 48.00% and 62.16%, respectively, as compared to the uninoculated/control plants. The photosynthetic pigments were also improved by bacterial inoculation as compared to untreated stress-exposed plants, i.e., increase in chlorophyll a, chlorophyll b, chlorophyll a + b, and carotenoid was d 25.94%, 10.65%, 20.35%, and 44.30%, respectively. Bacterial inoculation also resulted in osmotic adjustment (proline 8.76% and sugar 28.71%) and maintained the membrane stability (51.39%) which was also indicated by reduced malondialdehyde content (59.53% decrease). The antioxidant enzyme activities were also improved to 35.90% (superoxide dismutase), 59.61% (peroxide), and 33.33% (catalase) in inoculated stress-exposed plants as compared to the control plants. B. cereus inoculation also improved the uptake, bioaccumulation, and translocation of Cr in the plant. Data showed that B. cereus also increased Cr content in the root (2.71-fold) and shoot (4.01-fold), its bioaccumulation (2.71-fold in root and 4.03-fold in the shoot) and translocation (40%) was also high in B. nigra. The data revealed that B. cereus is a multifarious PGPR that efficiently tolerates heavy metal ions (Cr⁺³) and it can be used to enhance the growth and phytoextraction potential of B. nigra in heavy metal contaminated soil.     

Entanglement Transition in Hyperbranched Polyether‐Polyols

Are hyperbranched polymers capable of forming entanglements? This is the central issue of this contribution. Hyperbranched polyglycerol (hbPG) samples with different molecular weights (600–106 000 g · mol⁻¹), narrow polydispersities (1.2–1.8) and high degrees of branching (≈0.6) were prepared by anionic ring‐opening polymerization. The viscoelastic properties of these polymers with respect to molecular architecture and molar mass were investigated. At low molecular weights “classical” scaling behavior between zero shear viscosity and molecular weight can be observed, whereas between 3 000 and 10 000 g · mol⁻¹ a plateau‐like area is found. The results indicate entanglement dynamics when exceeding a critical molar mass ( ≈ 20 000 g · mol⁻¹) due to entangled hyperbranched polyglycerols.

     

Synthesis and molecular docking of some new 3,5-bis-(diazipine,pyrazolopyrimidine, pyrimidine,and pyrazole) pyridine derivatives and their in vitro and in vivo biological evaluation as potential antitumor agents

Bis enaminone derivative 6 was reactive enaminone to synthesize new heterocyclic compounds containing diazipine, pyrazolopyrimidine, triazolopyrimidine, and pyrazole moieties by reaction with different bifunctional reagents. Structures of new compounds were confirmed by analytical and spectral data. Moreover, the new compounds were screened in-vitro as antitumor agents for Ehrlich ascites at different concentration. The results showed the compounds 18 , 19, and 20a have a good activity. In addition to, the molecular docking of these mentioned compounds was studied using vascular endothelial growth factor receptor.     

Chiral ruthenium Lewis acid-catalyzed nitrile oxide cycloadditions

The synthesis of the chiral ligand (R,R)-BIPHOP-F is detailed. Its coordination to a cationic cyclopentadienyl ruthenium fragment generates [Ru (acetone)(R,R)-BIPHOP-F)Cp][SbF₆], a transition metal Lewis acid that catalyzes the [3+2] dipolar cycloaddition reaction between aryl nitrile oxides and α,β-unsaturated aldehydes to give chiral 2-isoxazolines with yields of 43-98% and asymmetric purity of 60-93% ee. The stereochemistry of the major enantiomer is S, consistent with an approach of the nitrile oxide to the C_α-Si face of the enal in the anti-s-trans conformation in the catalyst site.     

Mass spectrometric detection of protein, lipid and heme components of cytochrome c oxidase from R. sphaeroides and the stabilization of non-covalent complexes from the enzyme

The cytochrome c oxidase enzyme from the Rhodobacter sphaeroides bacteria exists as a complex of four peptide subunits, two hemes, and a variety of lipids and metal ions held together by non-covalent forces. While the native enzyme functions as an associated unit, this complex usually dissociates during MALDI- TOF analysis. Through the use of matrix additives such as sucrose, the complete complex and partial complexes can be stabilized in the MALDI-TOF experiment. The dissociation of the complex allows for the detection of the components of the enzyme. The direct detection of associated lipids from an aqueous solution of the intact enzyme may eliminate the need for enzyme disruption and lipid extraction. The partial dissociation of multisubunit enzymes in such experiments may allow for the determination of subunit-subunit and subunit-lipid interactions     

Hidden Heptacyclic Chiral N-Acyl Iminium Ions: A New Entry to Enantioenriched Polycyclic Azepanes and Azocanes by Superacid-Promoted Intramolecular Pictet-Spengler Reaction

Enantioenriched complex fused-tricyclic azepanes or bridged-polycyclic azocanes were constructed via a two-step sequence involving an enantioselective organocascade followed by superacid activation of the domino adduct. The activated oxa-bridged azepane acts as a key hidden heptacyclic chiral N-acyl iminium ion triggering a chemo- and diastereoselective intramolecular mono- or di-arylation.     

Operational Methods and Truncated Exponential-Based Mittag-Leffler Polynomials

This article deals with the introduction of truncated exponential-based Mittag-Leffler polynomials and derivation of their properties. The operational correspondence between these polynomials and Mittag-Leffler polynomials is established. An integral representation for these polynomials is also derived.     

Marilines A–C: Novel Phthalimidines from the Sponge‐Derived Fungus Stachylidium sp.

A marine‐derived fungus of the genus Stachylidium was isolated from the sponge Callyspongia cf. C. flammea. Chemical investigation of the bioactive fungal extract led to the isolation of the novel phthalimidine derivatives marilines A₁ ( 1 a ), A₂ ( 1 b ), B ( 2 ), and C ( 3 ). The absolute configurations of the enantiomeric compounds 1 a and 1 b were assigned by a combination of experimental circular dichroism (CD) investigations and quantum chemical CD calculations. The skeleton of marilines is most unusual, and its biosynthesis is suggested to require uncommon biochemical reactions in fungal secondary metabolism. Both enantiomers, marilines A₁ ( 1 a ) and A₂ ( 1 b ), inhibited human leukocyte elastase (HLE) with an IC₅₀ value of 0.86 μM .     

Synthesis of several new lanthanide Glimepiride complexes for evaluation of microbial activity

The complexation between lanthanide metal ions like Nd(III), Tb(III), and Er(III) with Glimepiride produces 1: 1 molar ratio (metal: Glimepiride) monodentate complexes of general formula: [M(GMP)(H₂O)₄]Cl₃·xH₂O, where: M = Nd, Tb, and Er, x = 1, 10, respectively. The structures of obtained compounds were assigned by IR, ¹H NMR and UV/Vis spectra. Themogravimetric analysis and kinetic thermodynamic parameters have proved the thermal stability of Glimepiride complexes. Obtained lanthanide complexes showed significant effect against some bacteria and fungi.