Chemical composition and antimicrobial activity of the essential oil of Anthemis altissima L. var. altissima

The essential oil obtained from the flowering parts of Anthemis altissima L. var. altissima was analysed by gas chromatography and gas chromatography mass spectroscopy. In this study, 34 compounds representing 98.76% of the essential oil were identified. The main components were α-terpineol (26.42%), β-pinene (9.23%), cis-chrysanthenyl acetate (6.30%), globulol (5.36%), n-tricosane (4.41%), terpinen-4-ol (4.08%) and 1,8 cineole (3.84%). Antibacterial activities of the essential oil and its two major components (α-terpineol and β-pinene) were determined using microdilution method against both Gram-positive (Staphylococcus aureus, Bacillus subtilis, Staphylococcus epidermidis) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae) bacteria. The essential oil showed a broad-spectrum antibacterial activity (MICs ranged from 3.13 to 6.25?μL?mL(-1)). It was found that α-terpineol with minimum inhibitory concentration (MIC) values of the range 0.87-1.56?μL?mL(-1) was a more potent antibacterial agent than β-pinene with MIC values of the range 1.56-6.25?μL?mL(-1). All of them, the essential oil, β-pinene and α-terpineol, were more effective against Gram-positive bacteria than Gram-negative ones.     

Novel and versatile methodology for synthesis of β-aryl-β-mercapto ketone derivatives as potential urease inhibitors

The objective was to obtain new scaffold of compounds possessing anti-urease activity. For this new and simple method for the synthesis of β-aryl-β-mercapto ketone derivatives based on Michael addition of thiophenol to chalcones in an ionic liquid as a solvent was improved. The products were obtained in good to moderate yields with high purity and characterized by spectral and elemental analyses. The activities of synthesized compounds were investigated as new inhibitors of jack bean urease. Among 22 synthesized compounds, all of them have shown inhibitory effect in micromolar range, and the most potent one has IC₅₀ = 6 μM compared to hydroxyurea IC₅₀ = 100 μM as a reference inhibitor. A docking study was performed using Autodock 4.2 in parallel to in vitro experiments to illustrate the corresponded binding affinities as well as binding site, and involved residues in interaction. These computational results complimented the experimental inhibition activity and enabled us to report a potent urease inhibitors based on β-aryl-β-mercapto ketone scaffold.     

A cost-effective form-stable PCM composite with modified paraffin and expanded perlite for thermal energy storage in concrete

Journal of Thermal Analysis and Calorimetry - High thermal conductivity in phase change materials (PCM) is preferred in thermal energy storage (TES) systems. Carbon additives are considered as...     

3D Printing in analytical sample preparation

In the last 5 years, additive manufacturing (three‐dimensional printing) has emerged as a highly valuable technology to advance the field of analytical sample preparation. Three‐dimensional printing enabled the cost‐effective and rapid fabrication of devices for sample preparation, especially in flow‐based mode, opening new possibilities for the development of automated analytical methods. Recent advances involve membrane‐based three‐dimensional printed separation devices fabricated by print‐pause‐print and multi‐material three‐dimensional printing, or improved three‐dimensional printed holders for solid‐phase extraction containing sorbent bead packings, extraction disks, fibers, and magnetic particles. Other recent developments rely on the direct three‐dimensional printing of extraction sorbents, the functionalization of commercial three‐dimensional printable resins, or the coating of three‐dimensional printed devices with functional micro/nanomaterials. In addition, improved devices for liquid–liquid extraction such as extraction chambers, or phase separators are opening new possibilities for analytical method development combined with high‐performance liquid chromatography. The present review outlines the current state‐of‐the‐art of three‐dimensional printing in analytical sample preparation.     

Phase Formation Studies of Lead(II) Copper(II) Oxotellurates: The Crystal Structures of Dimorphic PbCuTeO5, PbCuTe2O6, and [Pb2Cu2(Te4O11)](NO3)2

Two modifications of the oxotellurate(VI) PbCuTeO₅ were isolated as single crystals from product mixtures obtained from solid state reactions, whereas single crystals of the oxotellurates(IV) PbCuTe₂O₆ and [Pb₂Cu₂(Te₄O₁₁)](NO₃)₂ were grown under hydrothermal conditions. The crystal structures of all compounds comprise of characteristic coordination polyhedra, viz. nearly square [CuO₄] plaquettes for divalent copper, octahedral [TeO₆] units for hexavalent tellurium, trigonal‐pyramidal [TeO₃] and bisphenoidal [TeO₄] groups for tetravalent tellurium, and distorted [PbO_x] polyhedra for divalent lead. PbCuTeO₅ is dimorphic and crystallizes in a monoclinic and a triclinic modification, related by a translationengleiche group‐subgroup relation of index 2. PbCuTe₂O₆ represents the ideal composition of the rare mineral choloalite. The characteristic feature of the crystal structure of [Pb₂Cu₂(Te₄O₁₁)](NO₃)₂ is its layered set‐up, comprised of cationic [Pb₂Cu₂(Te₄O₁₁)]²⁺ ribbons (width approximately 6.7 Å) sandwiched between nitrate anions that are only weakly bound to the cationic layers.     

Two- and three-dimensional comparative study of heat transfer and pressure drop characteristics of nanofluids flow through a ventilated cubic cavity (part I: Newtonian nanofluids)

Journal of Thermal Analysis and Calorimetry - Through this paper, three-dimensional fluid flow and heat transfer of Al2O3 nanofluid within ventilated enclosures was taken into consideration....     

Kinetic Study of Radical Polymerization VIII. A Comprehensive Study of Solution Copolymerization of Vinyl Acetate and Methyl Acrylate by 1H‐NMR Spectroscopy

Radical copolymerization reaction of vinyl acetate (VA) and methyl acrylate (MA) was performed in a solution of benzene‐d₆ using benzoyl peroxide (BPO) as the initiator at 60°C. Kinetic studies of this copolymerization reaction were investigated by on‐line ¹H‐NMR spectroscopy. Individual monomer conversions vs. reaction time, which was followed by this technique, were used to calculate the overall monomer conversion, as well as the monomer mixture and the copolymer compositions as a function of time. Monomer reactivity ratios were calculated by various linear and nonlinear terminal models and also by simplified penultimate model with r _2(VA)=0 at low and medium/high conversions. Overall rate coefficient of copolymerization was calculated from the overall monomer conversion vs. time data and k _p  . k _t ^?0.5 was then estimated. It was observed that k _p  . k _t ^?0.5 increases with increasing the mole fraction of MA in the initial feed, indicating the increase in the polymerization rate with increasing MA concentration in the initial monomer mixture. The effect of mole fraction of MA in the initial monomer mixture on the drifts in the monomer mixture and copolymer compositions with reaction progress was also evaluated experimentally and theoretically.     

Nuclear model calculation for cyclotron production of 61Cu as a PET imaging

⁶¹Cu is positron emitter and can be used as the PET and molecular imaging. In this study cyclotron production of ⁶¹Cu via ⁶¹Ni(p,n)⁶¹Cu, ^natNi(p,x)⁶¹Cu, ^natNi(d,x)⁶¹Cu, ^natNi(α,x)⁶¹Cu, ^natZn(p,x)⁶¹Cu and ⁵⁹Co(α,2n)⁶¹Cu reactions was investigated. The ALICE/ASH (hybrid and GDH models) and TALYS-1.2 codes were used to calculate excitation functions for proton, alpha and deuteron induced on ^natNi, proton on ⁶¹Ni and ^natZn and also alpha-particle on ⁵⁹Co targets that lead to the production of ⁶¹Cu radioisotopes using intermediate energy accelerators. In addition, we compared the data obtained from in this study with the reported measurement by experimental data. Moreover, optimal thickness of the targets and physical yield were obtained by stopping and range of ions in matter code for each reaction. Eventually ⁶¹Ni(p,n)⁶¹Cu and ⁵⁹Co(α,2n)⁶¹Cu reaction to produce ⁶¹Cu in no-carrier added state with high production yield was suggested. Finally the ^natNi(p,x)⁶¹Cu reaction was employed to test the target preparation using electroplating technique.     

A Novel Hydrogen Peroxide Sensor Based on the Direct Electron Transfer of Catalase Immobilized on Nano‐Sized NiO/MWCNTs Composite Film

MWCNTs‐nanoNiO composite was used as a glassy carbon electrode modifier for construction of a novel catalase nanobiosensor for hydrogen peroxide. The immobilized catalase exhibited excellent electrocatalytic activity towards the reduction of H₂O₂. The resulting amperometric biosensor exhibited a linear response over a concentration range of 200 µM to 2.53 mM with a low detection limit of 19.0 µM. Electrochemical impedance measurements revealed that the modified electrode can be used for the sensitive detection of H₂O₂. The charge transfer resistance found to decrease significantly after enzymatic reaction of nanobiosensor with H₂O₂. The resulting impedance was highly sensitive to H₂O₂ over a linear range of 19–170 nM with a detection limit of 2.4 nM.