Porcine cytochrome 2A19 and 2E1

Cytochrome P450 (CYP) is a major group of enzymes, which conduct Phase I metabolism. Among commonly used animal models, the pig has been suggested as the most suitable model for investigating drug metabolism in human beings. Moreover, porcine CYP2A19 and CYP2E1 are responsible for the biotransformation of both endogenous and exogenous compounds such as 3‐methylindole (skatole), sex hormones and food compounds. However, little is known about the regulation of porcine CYP2A19 and CYP2E1. In this MiniReview, we summarise the current knowledge about the regulation of porcine CYP2A19 and CYP2E1 by environmental, biological and dietary factors. Finally, we reflect on the need for further research, to clarify the interaction between active feed components and the porcine CYP system.     

Comparative analysis of the results of tuberculosis questionnaire surveys among young persons

Sociosanitary monitoring evaluates the detected changes and predicts the health status of the population and its environment, establishes and eliminates its adverse human impact. Long-term sociological surveys for tuberculosis among the population of the Primorye Territory have revealed lower awareness in a young age group. Systemic antituberculosis propaganda, lectures with video films, discussions, questionnaire surveys in groups of young people will provide a more profound insight into the causes of tuberculosis, into the methods of its early detection and prevention. The results of questionnaire survey have been used in developing guidelines and differential programmes.     

Epidemiology of HIV infection in urban Burkina Faso

We conducted a cross-sectional study of sexually transmitted disease and HIV infections among a random sample of the 2364 adult population in 2000 in Bobo-Dioulasso, the second largest town in Burkina Faso. The prevalence of HIV infection was 5.2%. Risk factor analysis was conducted among sexually active men 20 to 34 years old and women 15 to 24 years old. Factors independently associated with HIV infection among men were having been married (adjusted odds ratio (aOR)=8.19 [1.70-39]), reporting more than two non-marital partners in the last 12 months (aOR=6.07 [1.14-32.4]), reporting a past urban residence other than Bobo-Dioulasso (aOR =6.37 [1.96-20.7] and having a positive serology for HSV-2 infection (aOR=12.0 [3.49-40.9]). Among women the factors were being Christian (aOR=3.73 [1.20-11.6]), having had a first sexual partner more than 24 years old (aOR =4.30 [1.35-13.6]) and having a positive serology for HSV-2 infection (aOR =4.40 [1.32-14.6]). HIV infection in Bobo-Dioulasso therefore depends on both exposure factors (sexual behaviours) and transmissibility cofactors (HSV-2).     

Bimetallic AgPd/UiO-66 Hybrid Catalysts for Propylene Glycol Oxidation into Lactic Acid

Different methods (the wetness impregnation of Ag and Pd precursors dissolved in water or acetonitrile solution, and the double solvent impregnation technique) were employed to immobilize Ag–Pd nanoparticles (NPs) into the pores of the microporous zirconium-based metal-organic framework known as UiO-66. The obtained materials were characterized by using nitrogen adsorption-desorption at −196 °C, powder X-ray diffraction, UV-Vis diffusion reflectance spectroscopy, and transition electron microscopy measurements. Special attention was paid to the acid and redox properties of the obtained materials, which were studied by using temperature-programmed desorption of ammonia (TPD-NH₃) and temperature-programmed reduction (TPR-H₂) methods. The use of a drying procedure prior to reduction was found to result in metallic NPs which, most likely, formed on the external surface and were larger than corresponding voids of the metal-organic framework. The formation of Ag–Pd alloy or monometallic Ag and Pd depended on the nature of both metal precursors and the impregnation solvent used. Catalytic activity of the AgPd/UiO-66 materials in propylene glycol oxidation was found to be a result of synergistic interaction between the components in AgPd alloyed NPs immobilized in the pore space and on the external surface of UiO-66. The key factor for consistent transformation of propylene glycol into lactic acid was the proximity between redox and acid-base species.     

Network Mesh Nanostructures in Cross‐Linked Poly(Dimethylsiloxane) Visualized by AFM

Mesh network structures are visualized by peak force tapping atomic force microscopy on cross‐linked poly(dimethylsiloxane) (PDMS) at the nanometer length scale. The images directly capture network mesh structures with mesh diameter values, from 10 to 16 nm at the free surface of PDMS. Perpendicular to the free surface, in cross‐sectional areas exposed by cryo‐fracturing, similar mesh structures are observed. When exposed to uniaxial stress, the circular mesh features become elongated, showing network deformation at the nanoscale, as a result of mechanical stress. Following Soxhlet solvent extraction the mesh‐like appearance remains unchanged, but mesh diameter values decrease, which are attributed to the removal of non‐crosslinked chains and silica filler.     

Effect of solvent nature on propylene glycol oxidation with tert-butyl hydroperoxide over metal–organic framework Cr-MIL-101

The effect of solvent nature on conversion, product yields and reaction kinetics of selective propylene glycol oxidation with tert-butyl hydroperoxide over porous chromium terephthalate Cr-MIL-101 used as a heterogeneous catalyst is considered. Differences in hydrogen bonding of propylene glycol molecules in different solvents and adsorption of components of the reaction mixture on the active sites of the catalyst are studied by Fourier-transformed infrared spectroscopy. The characteristics of the solvent are shown to play a key role in the process under consideration. In the case of aprotic solvents, the oxidant utilization efficiency, the propylene glycol conversion and the product yields are significantly higher in comparison with those in protic solvents. The protic solvents can adsorb on the active sites of the catalyst which leads to a decrease of their accessibility for the reagents. The initial rate of propylene glycol oxidation decreases linearly with the increasing of the diameter of molecules of the protic solvents. DFT calculations support the competitive adsorption of the molecules of protic solvents on Cr active sites of MIL-101. In the aprotic solvents, the reactivity and distribution of propylene glycol molecules in the solution are determined by the involvement of hydroxyl groups of the substrate into the intermolecular interactions. The ability of the aprotic solvents to break the hydrogen bond network in the associates of propylene glycol is responsible for the concentration of the substrate molecules in the pores of Cr-MIL-101. The highest selectivities towards hydroxyacetone for Cr-MIL-101 catalyst are obtained in solvents, where the initial rates of propylene glycol oxidation are the lowest ones.

The effect of solvent nature on conversion, product yields and reaction kinetics of selective propylene glycol oxidation with tert-butyl hydroperoxide over porous chromium terephthalate Cr-MIL-101 used as a heterogeneous catalyst is considered.     

Electrophilic alkylation of arenes with 5-bromopyrimidine en route to 4-aryl-5-alkynylpyrimidines

A new synthetic protocol for preparation of medicinally important 4-aryl-5-alkynylpyrimidines is described. The featured approach involves a sequence of chemo- and regioselective Brønsted acid-catalyzed electrophilic alkylation of arenes with 5-bromopyrimidine, followed by oxidative re-aromatization of the formed dihydropyrimidine ring. Finally, palladium-catalyzed Sonogashira cross-coupling reaction provided an end-game strategy.

Efficient assembly of 4-aryl-5-alkynylpyrimidines is described featuring novel Brønsted acid-catalyzed electrophilic alkylation of arenes with 5-bromopyrimidine as a key step.     

Synthesis and photoluminescence properties of hybrid 1D core–shell structured nanocomposites based on ZnO/polydopamine

In the present work, we report on the modelling of processes at the zinc oxide and polydopamine (ZnO/PDA) interface. The PDA layer was deposited onto ZnO nanorods (NRs) via chemical bath deposition. The defect concentrations in ZnO before and after PDA deposition were calculated and analysed. The ZnONRs/PDA core–shell nanostructures were studied by transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman and Fourier-transform infrared (FTIR) spectroscopy, photoluminescence (PL) measurements, and diffuse reflectance spectroscopy. The TEM and electron energy loss spectroscopy (EELS) measurements confirmed the conformal coating of PDA, while the PL emission from ZnO and ZnONRs/PDA samples showed a reduction of intensity after the PDA deposition. The decrease of defect concentration participating in PL and quantum efficiency explains the PL reduction. Finally, the observed decrease of activation energies and a shift of the PL peaks are attributed to the formation of an additional local electrical field between the PDA and ZnO nanostructures.

The results shown in this study provide a unique insight into the optical and electronic processes of the ZnO/PDA interface.