Fluorescent Probes from Aromatic Polycyclic Nitrile Oxides: Isoxazoles versus Dihydro-1λ3,3,2λ4-Oxazaborinines

Anthracenenitrile oxide undergoes 1,3-dipolar cycloaddition reaction with propargyl bromide affording the expected isoxazole as single regioisomer, suitably synthetically elaborated and functionalized with a protected triple bond. The introduction of a bromine atom at the position C10 of the anthracene moiety allows for inserting a variety of aromatic and heterocyclic substituents through Suzuki coupling. A two-way synthetic route can lead to simple isoxazole derivatives or, after N−O bond reductive cleavage and BF₃ complexation, enamino ketone boron complexes. The photophysical properties of both the substituted isoxazoles and the corresponding boron complexes were investigated to show the potentialities for the employment as fluorescent tags in imaging techniques. The quite good quantum yield values confirm the suitability of these compounds in the cellular environment. Scope and limitations of the methodology are discussed.     

Overview of Popular Techniques of Raman Spectroscopy and Their Potential in the Study of Plant Tissues

Raman spectroscopy is one of the main analytical techniques used in optical metrology. It is a vibration, marker-free technique that provides insight into the structure and composition of tissues and cells at the molecular level. Raman spectroscopy is an outstanding material identification technique. It provides spatial information of vibrations from complex biological samples which renders it a very accurate tool for the analysis of highly complex plant tissues. Raman spectra can be used as a fingerprint tool for a very wide range of compounds. Raman spectroscopy enables all the polymers that build the cell walls of plants to be tracked simultaneously; it facilitates the analysis of both the molecular composition and the molecular structure of cell walls. Due to its high sensitivity to even minute structural changes, this method is used for comparative tests. The introduction of new and improved Raman techniques by scientists as well as the constant technological development of the apparatus has resulted in an increased importance of Raman spectroscopy in the discovery and defining of tissues and the processes taking place in them.     

Evaluation of Hepatoprotective Activity and Oxidative Stress Reduction of Rosmarinus officinalis L. Shoots Tincture in Rats with Experimentally Induced Hepatotoxicity

Rosmarinus officinalis L. is a widely known species for its medicinal uses, that is also used as raw material for the food and cosmetic industry. The aim of the present study was to offer a novel perspective on the medicinal product originating from this species and to test its hepatoprotective activity. The tested sample consisted in a tincture obtained from the fresh young shoots. Compounds that are evaluated for this activity are polyphenols and terpenoids, that are identified and quantified by HPLC–UV–MS and GC–MS. Antioxidant activity was assessed in vitro, using the DPPH, FRAP and SO assays. Hepatoprotective activity was tested in rats with experimentally-induced hepatotoxicity. In the chemical composition of the tincture, phenolic diterpenes (carnosic acid, carnosol, rosmanol, rosmadial) and rosmarinic acid were found to be the majority compounds, alongside with 1,8-cineole, camphene, linalool, borneol and terpineol among monoterpenes. In vitro, the tested tincture proved significant antioxidant capacity. Results of the in vivo experiment showed that hepatoprotective activity is based on an antioxidant mechanism. In this way, the present study offers a novel perspective on the medicinal uses of the species, proving significant amounts of polyphenols and terpenes in the composition of the fresh young shoots tincture, that has proved hepatoprotective activity through an antioxidant mechanism.     

Temperature Window for Encapsulation of an Enzyme into Thermally Shrunk,CaCO3 Templated Polyelectrolyte Multilayer Capsules

Encapsulation of enzymes allows to preserve their biological activities in various environmental conditions, such as exposure to elevated temperature or to proteases. This is particularly relevant for in vivo applications, where proteases represent a severe obstacle to maintaining the activity of enzymes. Polyelectrolyte multilayer capsules are suitable for enzyme encapsulation, where CaCO₃ particles and temperature-dependent capsule formation are the best templates and the most adequate method, respectively. In this work, these two areas are combined and, ALP (alkaline phosphatase), which is a robust and therapeutically relevant enzyme, is encapsulated into thermally shrunk polyelectrolyte multilayer (PDADMAC/PSS)₄ capsules templated on calcium carbonate particles (original average diameter: ≈3.5 µm). The activity of the encapsulated enzyme and the optimal temperature range for encapsulation are investigated. The enzymatic activity is almost four times higher upon encapsulation when the temperature range for encapsulation is situated just above the glass transition temperature (40 °C), while its optimal conditions are dictated, on the one hand, by the enzyme activity (better at lower temperatures) and, on the other hand, by the size and mechanical properties of capsules (better at higher temperatures).     

Dehydrogenataion of Bicyclohexyl over Ni/Oxidized Sibunit Catalyst

Russian Journal of Physical Chemistry A - The dehydrogenation of bicyclohexyl over single-component Ni-containing catalyst supported on oxidized Sibunit containing 3, 10, and 20 wt % of Ni is...     

Prediction of octanol-water partition coefficients for the SAMPL6-$$\log P$$logP molecules using molecular dynamics simulations with OPLS-AA,AMBER and CHARMM force fields

Journal of Computer-Aided Molecular Design - All-atom molecular dynamics simulations with stratified alchemical free energy calculations were used to predict the octanol-water partition coefficient...     

Short-and long-range interaction parameters for polydimethylsiloxanes with different terminal groups

The paper discusses the behaviour of polydimethylsiloxanes with different terminal groups as induced by polymer molecular weight and solvent mixture composition in dilute solution.     

Synthesis of silazanylene-vinylene oligomers via catalytic polycondensation of divinyltetramethyldisilazane

Ruthenium (e. g., RuHCl(CO)(PPh₃)₃ and [RuCl₂(CO)₃]₂) and rhodium complexes (e. g., [RhX(cod)]₂, where X = Cl, OSiMe₃) appear to be the first effective catalysts for polycondensation of divinyltetramethyldisilazane ( I ) (ADPOL) to give poly(silazanylene-vinylene)s. Ruthenium catalysts give oligomers (M_w = 2 380, M_w/M_n = 1.21) and a mixture of trans-tactic oligomers, respectively, while rhodium complexes lead to the formation of a mixture of cyclic and linear oligomers.