Coordinative Approach to Mediated Electron Transfer: Ruthenium Complexed to Native Glucose Oxidase

Catalytically and electrocatalytically very active and stable are the complexes Ru(LL)-GO, which are extremely readily accessible from glucose oxidase (GO) and the Ru^II complexes cis-[Ru(LL)₂Cl₂] (LL=bpy, phen). These provide an unprecedentedly high amplification coefficient I/I_o (see cyclic voltammograms) even at high scan rates and, correspondingly, very high rates of intramolecular electron transfer.     

Specificity and Origin of the Stability of the Sr Isotopic Ratio in Champagne Wines

The ⁸⁷Sr/⁸⁶Sr ratio of 39 Champagnes from six different brands, originating from the whole “Appellation d’Origine Contrôlée” (AOC) Champagne was analyzed to establish a possible relation with the geographical origin. Musts (i.e., grape juice) and base wines were also analyzed to study the evolution of the Sr isotopic ratio during the elaboration process of sparkling wine. The results demonstrate that there is a very homogeneous Sr isotopic ratio (⁸⁷Sr/⁸⁶Sr = 0.70812, n = 37) and a narrow span of variability (2σ = 0.00007, n = 37). Moreover, the Sr concentrations in Champagnes have also low variability, which can be in part explained by the homogeneity of the bedrock in the AOC Champagne. Measurements of the ⁸⁷Sr/⁸⁶Sr ratio from musts and base wines show that blending during Champagne production plays a major role in the limited variability observed. Further, the ⁸⁷Sr/⁸⁶Sr of the musts were closely linked to the ⁸⁷Sr/⁸⁶Sr ratio of the vineyard soil. It appears that the ⁸⁷Sr/⁸⁶Sr of the product does not change during the elaboration process, but its variability decreases throughout the process due to blending. Both the homogeneity of the soil composition in the Champagne AOC and the blending process during the wine making process with several blending steps at different stages account for the unique and stable Sr isotopic signature of the Champagne wines.     

Adiabatic and nonadiabatic preparation of a ground-state coherence in an optically thick lambda medium

Fractional stimulated Raman adiabatic passage (f-STIRAP) is used to develop a method for preparation of a two-photon coherence between long-lived ground states of an optically thick ensemble of lambda atoms. Despite strong depletion and reshaping of preparation pulses in the course of propagation, this method provides a stable predetermined value of the coherence uniformly established along the sample, from input to the output. Both adiabatic and nonadiabatic preparation regimes are considered.     

Nanocrystalline aerogel VOx/MgO as a catalyst for oxidative dehydrogenation of propane

Nanocrystalline aerogel VO_x/MgO catalysts for the oxidative dehydrogenation of propane with high surface area and uniform vanadium distribution were synthesized by co-gelation followed by supercritical drying. The catalysts were shown to have superior performance compared to nanocrystalline VO_x/MgO catalysts prepared by impregnation.     

Intramolecular [4+2] cycloaddition of furfurylsubstituted homoallylamines to allylhalides,acryloyl chloride and maleic anhydride

Acylation of 4‐(furyl‐2)‐4‐R‐aminobut‐1‐enes and 4‐R‐4‐furfurylaminobut‐1‐enes with maleic anhydride, acryloyl chloride or allylhalides provided 3‐aza‐10‐oxatricyclo[5.2.1.0^1,5]decenes. The tricycles are formed via an initial amide formation followed by a stereoselective exo‐IMDAF (Intramolecular Diels‐Alder of Furan). In case of competing cycloaddition (for compounds possessing two furan or two dienophilic moieties) the most substituted fivemembered cycle is preferably annulated. Refluxing of 4‐R‐4‐furfurylaminobut‐1‐enes in acetic anhydride led to exo‐3‐aza‐11‐oxatricyclo[6.2.1.0^1,6]undecenes with the pseudoequatorial substituent R‐4. Treatment of 3‐aza‐10‐oxatricyclo[5.2.1.0^1,5]decenes with PPA at 90?110°C promoted cyclic ether opening, aromatization and intramolecular cyclization reactions sequence to give the corresponding tetracyclic compounds — tetrahydroisoindolo[2,1‐a]quinolines and tetrahydroisoindolo[2,1‐b][2]benzazepines in good yields. Unusual products of ipso‐substitution in aromatic ring were obtained on cyclization of N‐p‐R‐substituted 2‐allyl‐4‐oxo‐3‐aza‐10‐oxatricyclo[5.2.1.0^1,5]dec‐8‐enes.     

Effect of photonic crystal structure on the nonlinear optical anisotropy of birefringent porous silicon

Anisotropic photonic crystal structures consisting of birefringent porous silicon layers with alternating porosity were fabricated. The in-plane birefringence formed as a result of anisotropic etching in Si(110) results in unique multilayered structures with two distinct photonic bandgaps for orthogonal light polarizations. Nonlinear optical studies based on the third-harmonic generation from these structures demonstrate variation in the symmetry of the nonlinear optical response.     

Scattering of kinks of the sinh-deformed $$\varphi ^4$$ model

We consider the scattering of kinks of the sinh-deformed \(\varphi ^4\) model, which is obtained from the well-known \(\varphi ^4\) model by means of the deformation procedure. Depending on the initial velocity \(v_\mathrm {in}\) of the colliding kinks, different collision scenarios are realized. There is a critical value \(v_\mathrm {cr}\) of the initial velocity, which separates the regime of reflection (at \(v_\mathrm {in}>v_\mathrm {cr}\)) and that of a complicated interaction (at \(v_\mathrm {in}<v_\mathrm {cr}\)) with kinks’ capture and escape windows. Besides that, at \(v_\mathrm {in}\) below \(v_\mathrm {cr}\) we observe the formation of a bound state of two oscillons, as well as their escape at some values of \(v_\mathrm {in}\).     

Biomedical Investigations of Biodegradable PHAs

This work is a review of the results of biomedical studies of polymer devices (films, fibers, microparticles, 3D implants) made from resorbable PHAs synthesized by the bacterium Wautersia (Ralstonia) eutropha B5786, using the technology developed at the Institute of Biophysics of the Siberian Branch of the Russian Academy of Sciences. Two types of PHAs – polyhydroxybutyrate (PHB) and a hydroxybutyrate/hydroxyvalerate copolymer (PHB/PHV) – have been proven to be biocompatible in vitro in cultures of fibroblasts, endothelial cells, hepatocytes, and osteoblasts, and in short- and long-duration experiments on animals. Polymer films and membranes have been found to be usable as scaffolds for functioning cells and monofilament suture fibers – for stitching muscular-fascial wounds and in abdominal surgery. Ectopic bone formation assay and experiments with the model of segmental osteotomy showed that 3D PHB and PHB/HA implants can be used for reparative osteogenesis. The paper reports beneficial results of using polymers to repair bone defects in oral surgery.     

Synthesis and On‐Demand Gelation of Multifunctional Poly(ethylene glycol)‐Based Polymers

The synthesis of a novel photoreactive poly(ethylene glycol) (PEG)‐based polymer with caged carbonyl groups is reported. We further demonstrate its use for the on‐demand fabrication of hydrogels. For rapid gelation, a hydrazide‐functionalized PEG is used as the second component for the hydrogel preparation. The photoreactive PEG‐based polymer is designed for controlled cleavage of the protecting groups upon exposure to UV light releases free aldehyde moieties, which readily react with hydrazide groups in situ. This hydrogel system may find applications in controlled release drug delivery applications, when combined with in situ gelation. Furthermore, the possibility of forming gels specifically upon UV irradiation gives an opportunity for 3D fabrication of degradable scaffolds.