Estimate of stability of reconstruction of the exponential type

The problem of estimation of stability of reconstruction of the multiplicative exponential type is investigated. Some estimates of the stability are derived. Proceedings of the Seminar on Stability Problems for Stochastic Models, Hajdúszoboszló, Hungary, 1997, Part I.     

Employing sulfide-conductive solid electrolytes for the production of semiconducting sulfides with controlled composition and properties

Nonstoichiometry of sulfides of cadmium and lead is studied by the method of coulometric titration in electrochemical cells with sulfide-conductive solid electrolytes on the basis of MLn₂S₄. The range of the homogeneity region is estimated at temperatures 300 to 400°C. A feasible model for the formation of defects in nonstoichiometric sulfides of cadmium and lead is proposed.     

Reaction of 1-Aryl-3-methylpyrazol-5-ones with 2-Cyanoaryldiazonium Bisulfates

2-Cyanoaryldiazonium bisulfates, obtained by the action of nitrosyl sulfuric acid on isatin 3-hydrazone and its 5-bromo and 5-nitro derivatives, couple with 1-aryl-3-methylpyrazol-5-ones and form 4-arylhydrazones of 1-aryl-3-methylpyrazole-4,5-diones. It was established on the basis of data of IR, UV, and ¹H NMR spectra and of X-ray structural analysis that the coupling products exist in the hydrazone form stabilized by an intramolecular hydrogen bond.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 210–215, February, 2005.     

Synthesis of <Emphasis Type="Italic">N</Emphasis>-Arylsulfonyl-α-thienylglycines from <Emphasis Type="Italic">N</Emphasis>-(2,2,2-Trichloro-1-thienylethyl)arenesulfonamides

Reactions of N-(2,2,2-trichloroethylidene)arenesulfonamides with thiophene, 2-chlorothiophene, and 2,5-dichlorothiophene, as well as of N-(2,2,2-trichloro-1-hydroxyethyl)arenesulfonamides with 2-chlorothiophene, lead to formation of the corresponding N-(2,2,2-trichloro-1-thienylethyl)arenesulfonamides. Alkaline hydrolysis of the latter occurs selectively at the trichloromethyl group to give N-arylsulfonyl-α-thienylglycines.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 1, 2005, pp. 93–96.Original Russian Text Copyright © 2005 by Aizina, Rozentsveig, Ushakova, Levkovskaya, Mirskova.     

Olefin polymerization on immobilized zirconocene catalysts containing alkylaluminoxanes synthesized on the support surface

Ethylene and propylene polymerization on immobilized catalysts of composition MMT-H₂O/AlR₃/Zr-cene (MMT = montmorillonite) and on the corresponding homogeneous catalysts of composition Zr-cene-MAO (Zr-cene = rac-Et(Ind)₂ZrCl₂, rac-Me₂Si(Ind)₂ZrCl₂, rac-Me₂Si(2-Me-4-Ph-Ind)₂ZrCl₂, rac-1-(9-η⁵-Flu)2-(5,6-Cp2-Me-1-η⁵-Ind)Et]ZrCl₂) is considered. Here, the activating support for the zirconocenes is montmorillonite containing methylaluminoxane or isobutylaluminoxane synthesized directly on the monmorillonite surface by the partial hydrolysis of an alkylaluminum (AlMe₃, Al(i-Bu)₃, Al(i-Bu)₂H) with the mobile water of the support (MMT-H₂O/AlR₃). The MMT-H₂O/AlR₃ supports are demonstrated to be effective activators for ansa-zirconocenes. The catalytic properties of the immobilized systems (process kinetics and efficiency, the molar mass of the resulting polymer, and the structure of the macromolecules) depend on the activating support and the zirconocene precatalyst. The complexes of the MMT-H₂O/Al(i-Bu)₃ support with all zirconocene precatalysts are more active in propylene polymerization than the same complexes of MMT-H₂O/AlMe₃. The zirconcenes immobilized on MMT-H₂O/AlR₃ afford polyethylene and polypropylene with a higher molar mass than the corresponding homogeneous systems. Furthermore, immobilization causes activesite heterogeneity. As compared to the homogeneous single-site catalysts of composition Zr-cene-MAO, the corresponding catalysts immobilized on MMT-H₂O/AlR₃/Zr-cene are more stereospecific in the case of rac-Me₂Si(Ind)₂ZrCl₂ (C ₂ symmetry) and are less stereospecific in the case of rac-[1-(9-η⁵-Flu)2-(5,6-Cp-2-Me-1-η⁵-Ind)Et]ZrCl₂ (C _s symmetry).     

Capillary zone electrophoresis tandem mass spectrometry detects low concentration host cell impurities in monoclonal antibodies

We have evaluated CZE‐ESI‐MS/MS for detection of trace amounts of host cell protein impurities in recombinant therapeutics. Compared to previously published procedures, we have optimized the buffer pH used in the formation of a pH junction to increase injection volume. We also prepared a 5‐point calibration curve by spiking 12 standard proteins into a solution of a human mAb. A custom CZE‐MS/MS system was used to analyze the tryptic digest of this mixture without depletion of the antibody. CZE generated a ～70‐min separation window (～90‐min total analysis duration) and ～300‐peak capacity. We also analyzed the sample using ultra‐performance LC‐MS/MS. CZE‐MS/MS generated approximately five times higher base peak intensity and more peptide identifications for low‐level spiked proteins. Both methods detected all proteins spiked at ～100 ppm level with respect to the antibody.     

Synthetically Tuning the 2‐Position of Halogenated Quinolines: Optimizing Antibacterial and Biofilm Eradication Activities via Alkylation and Reductive Amination Pathways

Agents capable of eradicating bacterial biofilms are of great importance to human health as biofilm‐associated infections are tolerant to our current antibiotic therapies. We have recently discovered that halogenated quinoline (HQ) small molecules are: 1) capable of eradicating methicillin‐resistant Staphylococcus aureus (MRSA), methicillin‐resistant Staphylococcus epidermidis (MRSE) and vancomycin‐resistant Enterococcus faecium (VRE) biofilms, and 2) synthetic tuning of the 2‐position of the HQ scaffold has a significant impact on antibacterial and antibiofilm activities. Here, we report the chemical synthesis and biological evaluation of 39 HQ analogues that have a high degree of structural diversity at the 2‐position. We identified diverse analogues that are alkylated and aminated at the 2‐position of the HQ scaffold and demonstrate potent antibacterial (MIC≤0.39 μm ) and biofilm eradication (MBEC 1.0–93.8 μm ) activities against drug‐resistant Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecium strains while demonstrating <5 % haemolysis activity against human red blood cells (RBCs) at 200 μm . In addition, these HQs demonstrated low cytotoxicity against HeLa cells. Halogenated quinolines are a promising class of antibiofilm agents against Gram‐positive pathogens that could lead to useful treatments against persistent bacterial infections.