On the nonlocal stabilization by starting control of the normal equation generated from the Helmholtz system

We consider the problem of stabilization near zero of semilinear normal parabolic equations connected with the 3D Helmholtz system with periodic boundary conditions and arbitrary initial datum. This problem was previously studied in Fursikov and Shatina (2018). As it was recently revealed, the control function suggested in that work contains a term impeding transferring the stabilization construction on the 3D Helmholtz system. The main concern of this paper is to prove that this term is not necessary for the stabilization result, and therefore the control function can be changed by a proper way.     

Maghemite nanocrystal impregnation by hydrophobic surface modification of mesoporous silica

Here, we report the design of a hybrid inorganic/organic mesoporous material through simultaneous pore engineering and hydrophobic surface modification of the intramesochannels to improve the uptake of superparamagnetic maghemite nanocrystals via impregnation techniques. The mesoporous material of the SBA-15 type was functionalized in situ with thiol organo-siloxane groups. Restricting the addition of the thiol organo-siloxane to 2 mol % yielded an inorganic/organic hybrid material characterized by large pores and a well-ordered hexagonal p6mm mesophase. The hydrophobic surface modification promoted the incorporation of 7.5 nm maghemite (gamma-Fe2O3) nanocrystals, prepared through temperature-controlled decomposition of iron pentacarbonyl in organic solvents. The hydrophobic, oleic acid capped superparamagnetic maghemite nanocrystals were incorporated into the porous network via wet impregnation from organic suspensions. Combining diffraction, microscopy, and adsorption data confirmed the uptake of the nanocrystals within the intramesochannels of the silica host. Magnetization dependencies on magnetic field at different temperatures show a constriction in the loop around the origin, which indicates immobilization of maghemite nanocrystals inside the thiol-functionalized silica host.     

Indole-containing 2-Nitroethenylphosphonates: Synthesis and Structure

A method was developed for preparing first representatives of phosphorylated nitrovinylindoles, bis(2-chloroethyl) 1-(indol-3-yl)- and bis(2-chloroethyl) 1-(1-alkylindol-3-yl)-2-nitroethenylphosphonates, and the structures of these compounds were studied. The spectroscopic data and results of dipole moment measurements show that the molecules have E configuration with s-cis arrangement of the multiple bond and phosphoryl group. X-ray studies have shown that the molecules of the first compound, having the E-s-cis form in the solid phase also, exist in the crystal in the form of enantiomeric pairs. They are involved in inter- molecular hydrogen bonds to form infinite chains.     

Efficient switching from the 2,3′- to 2,2′-bipyrrole scaffold via the recyclization of 1-(benzoylmethylanilino)-3-imino-3H-2-cyanopyrrolizines: Crucial effect of the DBU organic superbase

The recyclization of readily available 1-(benzoylmethylanilino)-3-imino-3H-2-cyanopyrrolizines using the DBU organic superbase, unexpectedly gave 2,2′-bipyrroles with amino, keto and cyano functional groups on one of the pyrrole rings in 83–94% yield. Previously, using the KOH/DMSO system, this recyclization led to 2,3′-bipyrroles in low yields (12–26%). This selective switching was explained by sterically hindered access for the intermediate carbanion to the 1-position of the pyrrolizine ring due to the large size of the accompanying DBU countercation. The new methodology opens an efficient route to pharmaceutically and synthetically useful densely functionalized 2,2′-bipyrroles.     

Synthesis and hydrolysis of 5-nitrofurandicarboxylic acid esters

A method of the hydrolysis of 5-nitrofurandicarboxylic acid testers is proposed. The difference in the reactivities of the ester groups attached to the furan ring and in the side chain is explained by the effect of steric factors. It is shown that the direction of hydrolysis is determined by the structure of the alkyl substituent in the ester group. The mechanisms of the hydrolysis are discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 311–313, March, 1977.     

Phosphorylnitrile oxides. 5. Reactions of 3-(dialkoxyphosphoryl)isoxazoles and -isoxazolines with nucleophilic reagents

3-Phosphotylated isoxazoles and isoxazolines react with nucleophiles either with cleavage of the P-C bond and subsequent ring opening or with retention of the heterocyclic ring depending on the structure of the ring substituents, nature of the nucleophile, and reaction conditions. This permits the selective chemical modification of the starting compounds.Kazan State Technological University, Kazan 420015. Institute of Physiologically Active Compounds, Russian Academy of Sciences, Chernogolovka 142432. A. I. Gertsen Russian State Pedogogical University, St. Petersburg 191186. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 821–828, June, 1994. Original article submitted April 28, 1994.     

Synthesis of Phosphorylated Nitrocyclohexenes and Nitronorbornenes

Russian Journal of General Chemistry -     

Plasmon microscopy and imaging ellipsometry of Artrobacter oxydans attached on polymer films

The attachment of Artrobacter oxydans 1,388 on a newly synthesized biodegradable copolymer of poly-(hexanlactam)-co-block-poly-(delta-valerolactone) is investigated by optical, microscopic and biochemical methods. The potentials of surface plasmon microscopy and imaging ellipsometry for detecting microorganisms when Al films are used to excite plasmons is assessed by comparing images obtained by these methods with dark field microscopy pictures. The experimental results demonstrate that in this case imaging ellipsometry and plasmon microscopy in transmission are promising methods and can be used in optical sensors for monitoring cell adhesion.     

Evaluation of boronate-containing polymer brushes and gels as substrates for carbohydrate-mediated adhesion and cultivation of animal cells

Boronate-containing thin polyacrylamide gels (B-Gel), polymer brushes (B-Brush) and chemisorbed organosilane layers (B-COSL) were prepared on the surface of glass slides and studied as substrates for carbohydrate-mediated cell adhesion. B-COSL- and B-Brush-modified glass samples exhibited multiple submicron structures densely and irregularly distributed on the glass surface, as found by scanning electron microscopy and atomic force microscopy. B-Gel was ca. 0.1 mm thick and contained pores with effective size of 1–2 μm in the middle and of 5–20 μm on the edges of the gel sample as found by confocal laser scanning microscopy. Evidence for the presence of phenylboronic acid in the samples was given by time-of-flight secondary ion mass-spectrometry (ToF SIMS), contact angle measurements performed in the presence of fructose, and staining with Alizarin Red S dye capable of formation specific, fluorescent complexes with boronic acids. A comparative study of adhesion and cultivation of animal cells on the above substrates was carried out using murine hybridoma M2139 cell line as a model. M2139 cells adhered to the substrates in the culture medium without glucose or sodium pyruvate at pH 8.0, and then were cultivated in the same medium at pH 7.2 for 4 days. It was found that the substrates of B-Brush type were superior both regarding cell adhesion and viability of the adhered cells, among the substrates studied. MTT assay confirmed proliferation of M2139 cells on B-Brush substrates. Some cell adhesion was also registered in the macropores of B-Gel substrate. The effects of surface microstructure of the boronate-containing polymers on cell adhesion are discussed. Transparent glass substrates grafted with boronate-containing copolymers offer good prospects for cell adhesion studies and development of cell-based assays.